21121306455204 has 24 divisors (see below), whose sum is σ = 54758942661920. Its totient is φ = 7040435485032.

The previous prime is 21121306455203. The next prime is 21121306455217. The reversal of 21121306455204 is 40255460312112.

21121306455204 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 1 + 3 + 0 + 645 + 5 + 2 + 0 + 4 = 666.

It is a super-2 number, since 2×21121306455204² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21121306455203) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97783826074 + ... + 97783826289.

Almost surely, 2^{21121306455204} is an apocalyptic number.

It is an amenable number.

21121306455204 is an abundant number, since it is smaller than the sum of its proper divisors (33637636206716).

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

21121306455204 is a wasteful number, since it uses less digits than its factorization.

21121306455204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195567652376 (or 195567652368 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

Adding to 21121306455204 its reverse (40255460312112), we get a palindrome (61376766767316).

The spelling of 21121306455204 in words is "twenty-one trillion, one hundred twenty-one billion, three hundred six million, four hundred fifty-five thousand, two hundred four".