642659940 has 192 divisors, whose sum is σ = 2204294400. Its totient is φ = 154441728.

The previous prime is 642659911. The next prime is 642659957. The reversal of 642659940 is 49956246.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 300796 + ... + 302924.

It is an arithmetic number, because the mean of its divisors is an integer number (11480700).

Almost surely, 2^642659940 is an apocalyptic number.

642659940 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 642659940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1102147200).

642659940 is an abundant number, since it is smaller than the sum of its proper divisors (1561634460).

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

642659940 is a wasteful number, since it uses less digits than its factorization.

642659940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2203 (or 2195 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 45.

The square root of 642659940 is about 25350.7384507828. The cubic root of 642659940 is about 862.9661147852.

It can be divided in two parts, 6426 and 59940, that added together give a palindrome (66366).

The spelling of 642659940 in words is "six hundred forty-two million, six hundred fifty-nine thousand, nine hundred forty".