21165666656112 has 160 divisors (see below), whose sum is σ = 67209800440320. Its totient is φ = 6323502528000.

The previous prime is 21165666656111. The next prime is 21165666656117.

21165666656112 is nontrivially palindromic in base 10.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21165666656111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31029189 + ... + 31703972.

It is an arithmetic number, because the mean of its divisors is an integer number (420061252752).

Almost surely, 2^{21165666656112} is an apocalyptic number.

21165666656112 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21165666656112 is an abundant number, since it is smaller than the sum of its proper divisors (46044133784208).

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

21165666656112 is a wasteful number, since it uses less digits than its factorization.

21165666656112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62733260 (or 62733248 counting only the distinct ones).

The product of its digits is 4665600, while the sum is 54.

The spelling of 21165666656112 in words is "twenty-one trillion, one hundred sixty-five billion, six hundred sixty-six million, six hundred fifty-six thousand, one hundred twelve".