642686400 has 588 divisors, whose sum is σ = 2581884600. Its totient is φ = 156764160.

The previous prime is 642686399. The next prime is 642686431. The reversal of 642686400 is 4686246.

It is a happy number.

642686400 is a `hidden beast` number, since 6 + 4 + 2 + 6 + 8 + 640 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 22161586 + ... + 22161614.

Almost surely, 2^642686400 is an apocalyptic number.

642686400 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 642686400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1290942300).

642686400 is an abundant number, since it is smaller than the sum of its proper divisors (1939198200).

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

642686400 is a wasteful number, since it uses less digits than its factorization.

642686400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88 (or 58 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 642686400 is about 25351.2603236999. The cubic root of 642686400 is about 862.9779581509.

The spelling of 642686400 in words is "six hundred forty-two million, six hundred eighty-six thousand, four hundred".