642631680 has 288 divisors, whose sum is σ = 2350857600. Its totient is φ = 161906688.

The previous prime is 642631679. The next prime is 642631687. The reversal of 642631680 is 86136246.

642631680 is a `hidden beast` number, since 642 + 6 + 3 + 1 + 6 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×642631680² = 825950952279244800, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (642631687) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1750857 + ... + 1751223.

It is an arithmetic number, because the mean of its divisors is an integer number (8162700).

Almost surely, 2^642631680 is an apocalyptic number.

642631680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642631680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1175428800).

642631680 is an abundant number, since it is smaller than the sum of its proper divisors (1708225920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642631680 is a wasteful number, since it uses less digits than its factorization.

642631680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419 (or 396 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 642631680 is about 25350.1810644421. The cubic root of 642631680 is about 862.9534653894.

The spelling of 642631680 in words is "six hundred forty-two million, six hundred thirty-one thousand, six hundred eighty".