641667138 has 32 divisors (see below), whose sum is σ = 1502444160. Its totient is φ = 178861440.

The previous prime is 641667083. The next prime is 641667149. The reversal of 641667138 is 831766146.

It is a super-2 number, since 2×641667138² = 823473431978222088, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 641667138.

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, 184593 + ... + 188036.

It is an arithmetic number, because the mean of its divisors is an integer number (46951380).

Almost surely, 2^641667138 is an apocalyptic number.

641667138 is an abundant number, since it is smaller than the sum of its proper divisors (860777022).

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

641667138 is a wasteful number, since it uses less digits than its factorization.

641667138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372682.

The product of its digits is 145152, while the sum is 42.

The square root of 641667138 is about 25331.1495593864. The cubic root of 641667138 is about 862.5215063740.

The spelling of 641667138 in words is "six hundred forty-one million, six hundred sixty-seven thousand, one hundred thirty-eight".