642064920 has 256 divisors, whose sum is σ = 2289530880. Its totient is φ = 141004800.

The previous prime is 642064919. The next prime is 642064931. The reversal of 642064920 is 29460246.

It is a happy number.

It is a Cunningham number, because it is equal to 25339²-1.

It is a super-2 number, since 2×642064920² = 824494722989212800, which contains 22 as substring.

It is a congruent number.

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, 3547230 + ... + 3547410.

It is an arithmetic number, because the mean of its divisors is an integer number (8943480).

Almost surely, 2^642064920 is an apocalyptic number.

642064920 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 642064920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1144765440).

642064920 is an abundant number, since it is smaller than the sum of its proper divisors (1647465960).

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

642064920 is a wasteful number, since it uses less digits than its factorization.

642064920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346 (or 342 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 642064920 is about 25338.9999802676. Note that the first 4 decimals coincide. The cubic root of 642064920 is about 862.6997008702.

The spelling of 642064920 in words is "six hundred forty-two million, sixty-four thousand, nine hundred twenty".