21356253773166 has 64 divisors (see below), whose sum is σ = 46167087149568. Its totient is φ = 6547029648768.

The previous prime is 21356253773161. The next prime is 21356253773219. The reversal of 21356253773166 is 66137735265312.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21356253773161) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 57837120 + ... + 58205196.

It is an arithmetic number, because the mean of its divisors is an integer number (721360736712).

Almost surely, 2^{21356253773166} is an apocalyptic number.

21356253773166 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21356253773166 is an abundant number, since it is smaller than the sum of its proper divisors (24810833376402).

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

21356253773166 is a wasteful number, since it uses less digits than its factorization.

21356253773166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 370825.

The product of its digits is 28576800, while the sum is 57.

The spelling of 21356253773166 in words is "twenty-one trillion, three hundred fifty-six billion, two hundred fifty-three million, seven hundred seventy-three thousand, one hundred sixty-six".