21638036197872 has 30 divisors (see below), whose sum is σ = 60556448526392. Its totient is φ = 7212678732576.

The previous prime is 21638036197853. The next prime is 21638036197907. The reversal of 21638036197872 is 27879163083612.

21638036197872 is a `hidden beast` number, since 2 + 1 + 6 + 3 + 8 + 0 + 3 + 619 + 7 + 8 + 7 + 2 = 666.

It is a super-2 number, since 2×21638036197872² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 75132069988 + ... + 75132070275.

Almost surely, 2^{21638036197872} is an apocalyptic number.

It is an amenable number.

21638036197872 is an abundant number, since it is smaller than the sum of its proper divisors (38918412328520).

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

21638036197872 is a wasteful number, since it uses less digits than its factorization.

21638036197872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150264140277 (or 150264140268 counting only the distinct ones).

The product of its (nonzero) digits is 36578304, while the sum is 63.

The spelling of 21638036197872 in words is "twenty-one trillion, six hundred thirty-eight billion, thirty-six million, one hundred ninety-seven thousand, eight hundred seventy-two".