21551100342520 has 128 divisors (see below), whose sum is σ = 59756581785600. Its totient is φ = 6829323494400.

The previous prime is 21551100342517. The next prime is 21551100342581. The reversal of 21551100342520 is 2524300115512.

It is a super-2 number, since 2×21551100342520² (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 31 ways as a sum of consecutive naturals, for example, 49183816 + ... + 49620055.

It is an arithmetic number, because the mean of its divisors is an integer number (466848295200).

Almost surely, 2^{21551100342520} is an apocalyptic number.

21551100342520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21551100342520 is an abundant number, since it is smaller than the sum of its proper divisors (38205481443080).

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

21551100342520 is a wasteful number, since it uses less digits than its factorization.

21551100342520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98803949 (or 98803945 counting only the distinct ones).

The product of its (nonzero) digits is 12000, while the sum is 31.

The spelling of 21551100342520 in words is "twenty-one trillion, five hundred fifty-one billion, one hundred million, three hundred forty-two thousand, five hundred twenty".