21815553637272 has 64 divisors (see below), whose sum is σ = 58307704865280. Its totient is φ = 6777647718912.

The previous prime is 21815553637253. The next prime is 21815553637331. The reversal of 21815553637272 is 27273635551812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 259518628 + ... + 259602675.

It is an arithmetic number, because the mean of its divisors is an integer number (911057888520).

Almost surely, 2^{21815553637272} is an apocalyptic number.

It is an amenable number.

21815553637272 is an abundant number, since it is smaller than the sum of its proper divisors (36492151228008).

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

21815553637272 is a wasteful number, since it uses less digits than its factorization.

21815553637272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 519121432 (or 519121428 counting only the distinct ones).

The product of its digits is 21168000, while the sum is 57.

The spelling of 21815553637272 in words is "twenty-one trillion, eight hundred fifteen billion, five hundred fifty-three million, six hundred thirty-seven thousand, two hundred seventy-two".