21621266274165 has 8 divisors (see below), whose sum is σ = 34594026038688. Its totient is φ = 11531342012880.

The previous prime is 21621266274163. The next prime is 21621266274191. The reversal of 21621266274165 is 56147266212612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21621266274165 - 2¹ = 21621266274163 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621266274163) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 720708875791 + ... + 720708875820.

It is an arithmetic number, because the mean of its divisors is an integer number (4324253254836).

Almost surely, 2^{21621266274165} is an apocalyptic number.

It is an amenable number.

21621266274165 is a deficient number, since it is larger than the sum of its proper divisors (12972759764523).

21621266274165 is a wasteful number, since it uses less digits than its factorization.

21621266274165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1441417751619.

The product of its digits is 2903040, while the sum is 51.

The spelling of 21621266274165 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred sixty-six million, two hundred seventy-four thousand, one hundred sixty-five".