638574897690 has 24 divisors (see below), whose sum is σ = 1660294734228. Its totient is φ = 170286639360.

The previous prime is 638574897683. The next prime is 638574897749. The reversal of 638574897690 is 96798475836.

638574897690 is a `hidden beast` number, since 6 + 3 + 8 + 57 + 489 + 7 + 6 + 90 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 529391573649 + 109183324041 = 727593^2 + 330429^2 .

It is a super-2 number, since 2×638574897690² (a number of 24 digits) contains 22 as substring.

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, 3547638231 + ... + 3547638410.

Almost surely, 2^638574897690 is an apocalyptic number.

638574897690 is an abundant number, since it is smaller than the sum of its proper divisors (1021719836538).

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

638574897690 is a wasteful number, since it uses less digits than its factorization.

638574897690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7095276654 (or 7095276651 counting only the distinct ones).

The product of its (nonzero) digits is 548674560, while the sum is 72.

The spelling of 638574897690 in words is "six hundred thirty-eight billion, five hundred seventy-four million, eight hundred ninety-seven thousand, six hundred ninety".