638632980 has 36 divisors (see below), whose sum is σ = 1937187252. Its totient is φ = 170302080.

The previous prime is 638632963. The next prime is 638633011. The reversal of 638632980 is 89236836.

638632980 is a `hidden beast` number, since 6 + 3 + 8 + 632 + 9 + 8 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 106131204 + 532501776 = 10302^2 + 23076^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1773801 + ... + 1774160.

It is an arithmetic number, because the mean of its divisors is an integer number (53810757).

Almost surely, 2^638632980 is an apocalyptic number.

638632980 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

638632980 is an abundant number, since it is smaller than the sum of its proper divisors (1298554272).

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

638632980 is a wasteful number, since it uses less digits than its factorization.

638632980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3547976 (or 3547971 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The square root of 638632980 is about 25271.1887334173. The cubic root of 638632980 is about 861.1598646124.

The spelling of 638632980 in words is "six hundred thirty-eight million, six hundred thirty-two thousand, nine hundred eighty".