638979120 has 240 divisors, whose sum is σ = 2433281760. Its totient is φ = 148967424.

The previous prime is 638979113. The next prime is 638979157. The reversal of 638979120 is 21979836.

638979120 is a `hidden beast` number, since 638 + 9 + 7 + 9 + 1 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

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 47 ways as a sum of consecutive naturals, for example, 176044 + ... + 179636.

It is an arithmetic number, because the mean of its divisors is an integer number (10138674).

Almost surely, 2^638979120 is an apocalyptic number.

638979120 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 638979120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1216640880).

638979120 is an abundant number, since it is smaller than the sum of its proper divisors (1794302640).

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

638979120 is a wasteful number, since it uses less digits than its factorization.

638979120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3644 (or 3635 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The square root of 638979120 is about 25278.0363161382. The cubic root of 638979120 is about 861.3154198100.

The spelling of 638979120 in words is "six hundred thirty-eight million, nine hundred seventy-nine thousand, one hundred twenty".