21669664412016 has 240 divisors, whose sum is σ = 66583834611840. Its totient is φ = 6803492693760.

The previous prime is 21669664412009. The next prime is 21669664412041. The reversal of 21669664412016 is 61021446696612.

21669664412016 is a `hidden beast` number, since 2 + 166 + 9 + 6 + 6 + 441 + 20 + 16 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 11932051 + ... + 13627661.

It is an arithmetic number, because the mean of its divisors is an integer number (277432644216).

Almost surely, 2^{21669664412016} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21669664412016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33291917305920).

21669664412016 is an abundant number, since it is smaller than the sum of its proper divisors (44914170199824).

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

21669664412016 is a wasteful number, since it uses less digits than its factorization.

21669664412016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1695826 (or 1695808 counting only the distinct ones).

The product of its (nonzero) digits is 4478976, while the sum is 54.

The spelling of 21669664412016 in words is "twenty-one trillion, six hundred sixty-nine billion, six hundred sixty-four million, four hundred twelve thousand, sixteen".