21866319689544 has 96 divisors (see below), whose sum is σ = 65138961644640. Its totient is φ = 6626157452640.

The previous prime is 21866319689483. The next prime is 21866319689563. The reversal of 21866319689544 is 44598691366812.

21866319689544 is a `hidden beast` number, since 2 + 1 + 8 + 6 + 6 + 3 + 19 + 68 + 9 + 544 = 666.

It is a super-2 number, since 2×21866319689544² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 113990902 + ... + 114182565.

It is an arithmetic number, because the mean of its divisors is an integer number (678530850465).

Almost surely, 2^{21866319689544} is an apocalyptic number.

21866319689544 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21866319689544 is an abundant number, since it is smaller than the sum of its proper divisors (43272641955096).

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

21866319689544 is a wasteful number, since it uses less digits than its factorization.

21866319689544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228173512 (or 228173483 counting only the distinct ones).

The product of its digits is 537477120, while the sum is 72.

The spelling of 21866319689544 in words is "twenty-one trillion, eight hundred sixty-six billion, three hundred nineteen million, six hundred eighty-nine thousand, five hundred forty-four".