21655212000020 has 24 divisors (see below), whose sum is σ = 45657124275168. Its totient is φ = 8627574500000.

The previous prime is 21655212000013. The next prime is 21655212000043. The reversal of 21655212000020 is 2000021255612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2156888606 + ... + 2156898645.

It is an arithmetic number, because the mean of its divisors is an integer number (1902380178132).

Almost surely, 2^{21655212000020} is an apocalyptic number.

21655212000020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21655212000020 is an abundant number, since it is smaller than the sum of its proper divisors (24001912275148).

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

21655212000020 is a wasteful number, since it uses less digits than its factorization.

21655212000020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4313787511 (or 4313787509 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

Adding to 21655212000020 its reverse (2000021255612), we get a palindrome (23655233255632).

The spelling of 21655212000020 in words is "twenty-one trillion, six hundred fifty-five billion, two hundred twelve million, twenty", and thus it is an aban number.