638691478019 has 16 divisors (see below), whose sum is σ = 741532698816. Its totient is φ = 538812518400.

The previous prime is 638691478013. The next prime is 638691478057. The reversal of 638691478019 is 910874196836.

It is a cyclic number.

It is not a de Polignac number, because 638691478019 - 2⁴ = 638691478003 is a prime.

It is a super-2 number, since 2×638691478019² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (638691478013) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2475542 + ... + 2721339.

It is an arithmetic number, because the mean of its divisors is an integer number (46345793676).

Almost surely, 2^638691478019 is an apocalyptic number.

638691478019 is a deficient number, since it is larger than the sum of its proper divisors (102841220797).

638691478019 is a wasteful number, since it uses less digits than its factorization.

638691478019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5197166.

The product of its (nonzero) digits is 15676416, while the sum is 62.

The spelling of 638691478019 in words is "six hundred thirty-eight billion, six hundred ninety-one million, four hundred seventy-eight thousand, nineteen".