21615951222720 has 168 divisors, whose sum is σ = 76748248636800. Its totient is φ = 5578309969920.

The previous prime is 21615951222713. The next prime is 21615951222727. The reversal of 21615951222720 is 2722215951612.

It is a happy number.

21615951222720 is a `hidden beast` number, since 2 + 1 + 6 + 1 + 595 + 12 + 2 + 27 + 20 = 666.

It is an interprime number because it is at equal distance from previous prime (21615951222713) and next prime (21615951222727).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21615951222727) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 120967795 + ... + 121146354.

Almost surely, 2^{21615951222720} is an apocalyptic number.

21615951222720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21615951222720 is an abundant number, since it is smaller than the sum of its proper divisors (55132297414080).

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

21615951222720 is a wasteful number, since it uses less digits than its factorization.

21615951222720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242114203 (or 242114190 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 45.

The spelling of 21615951222720 in words is "twenty-one trillion, six hundred fifteen billion, nine hundred fifty-one million, two hundred twenty-two thousand, seven hundred twenty".