21988437555015 has 48 divisors (see below), whose sum is σ = 38250632922528. Its totient is φ = 11684913666048.

The previous prime is 21988437554977. The next prime is 21988437555031. The reversal of 21988437555015 is 51055573488912.

21988437555015 is a `hidden beast` number, since 2 + 1 + 9 + 8 + 8 + 4 + 3 + 75 + 550 + 1 + 5 = 666.

It is not a de Polignac number, because 21988437555015 - 2¹⁹ = 21988437030727 is a prime.

It is a super-2 number, since 2×21988437555015² (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 47 ways as a sum of consecutive naturals, for example, 212075067 + ... + 212178723.

It is an arithmetic number, because the mean of its divisors is an integer number (796888185886).

Almost surely, 2^{21988437555015} is an apocalyptic number.

21988437555015 is a deficient number, since it is larger than the sum of its proper divisors (16262195367513).

21988437555015 is a wasteful number, since it uses less digits than its factorization.

21988437555015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120608 (or 120605 counting only the distinct ones).

The product of its (nonzero) digits is 60480000, while the sum is 63.

The spelling of 21988437555015 in words is "twenty-one trillion, nine hundred eighty-eight billion, four hundred thirty-seven million, five hundred fifty-five thousand, fifteen".