638979350811 has 8 divisors (see below), whose sum is σ = 859788729360. Its totient is φ = 422078103072.

The previous prime is 638979350809. The next prime is 638979350887. The reversal of 638979350811 is 118053979836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 638979350811 - 2¹ = 638979350809 is a prime.

It is a super-2 number, since 2×638979350811² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (638979350011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 977032320 + ... + 977032973.

It is an arithmetic number, because the mean of its divisors is an integer number (107473591170).

Almost surely, 2^638979350811 is an apocalyptic number.

638979350811 is a deficient number, since it is larger than the sum of its proper divisors (220809378549).

638979350811 is a wasteful number, since it uses less digits than its factorization.

638979350811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1954065405.

The product of its (nonzero) digits is 9797760, while the sum is 60.

The spelling of 638979350811 in words is "six hundred thirty-eight billion, nine hundred seventy-nine million, three hundred fifty thousand, eight hundred eleven".