638632992 has 96 divisors (see below), whose sum is σ = 1741824000. Its totient is φ = 204731648.

The previous prime is 638632963. The next prime is 638633011. The reversal of 638632992 is 299236836.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (48).

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, 265009 + ... + 267407.

It is an arithmetic number, because the mean of its divisors is an integer number (18144000).

Almost surely, 2^638632992 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 638632992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (870912000).

638632992 is an abundant number, since it is smaller than the sum of its proper divisors (1103191008).

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

638632992 is a wasteful number, since it uses less digits than its factorization.

638632992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2518 (or 2510 counting only the distinct ones).

The product of its digits is 839808, while the sum is 48.

The square root of 638632992 is about 25271.1889708419. The cubic root of 638632992 is about 861.1598700062.

The spelling of 638632992 in words is "six hundred thirty-eight million, six hundred thirty-two thousand, nine hundred ninety-two".