642809992 has 64 divisors (see below), whose sum is σ = 1339545600. Its totient is φ = 286755840.

The previous prime is 642809987. The next prime is 642810019. The reversal of 642809992 is 299908246.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1262634 + ... + 1263142.

It is an arithmetic number, because the mean of its divisors is an integer number (20930400).

Almost surely, 2^642809992 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642809992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (669772800).

642809992 is an abundant number, since it is smaller than the sum of its proper divisors (696735608).

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

642809992 is a wasteful number, since it uses less digits than its factorization.

642809992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 766 (or 762 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 49.

The square root of 642809992 is about 25353.6977973628. The cubic root of 642809992 is about 863.0332730165.

The spelling of 642809992 in words is "six hundred forty-two million, eight hundred nine thousand, nine hundred ninety-two".