21637036890 has 48 divisors (see below), whose sum is σ = 64292911488. Its totient is φ = 4945608288.

The previous prime is 21637036871. The next prime is 21637036891. The reversal of 21637036890 is 9863073612.

21637036890 is a `hidden beast` number, since 2 + 1 + 637 + 0 + 3 + 6 + 8 + 9 + 0 = 666.

It is a super-2 number, since 2×21637036890² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21637036891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17171622 + ... + 17172881.

It is an arithmetic number, because the mean of its divisors is an integer number (1339435656).

Almost surely, 2^21637036890 is an apocalyptic number.

21637036890 is an abundant number, since it is smaller than the sum of its proper divisors (42655874598).

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

21637036890 is a wasteful number, since it uses less digits than its factorization.

21637036890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34344523 (or 34344520 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 45.

The spelling of 21637036890 in words is "twenty-one billion, six hundred thirty-seven million, thirty-six thousand, eight hundred ninety".