21620551613461 has 8 divisors (see below), whose sum is σ = 22987337770584. Its totient is φ = 20264319790080.

The previous prime is 21620551613449. The next prime is 21620551613497. The reversal of 21620551613461 is 16431615502612.

It can be written as a sum of positive squares in 4 ways, for example, as 12712654761361 + 8907896852100 = 3565481^2 + 2984610^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21620551613461 - 2³³ = 21611961678869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21620551613161) 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, 2638579210 + ... + 2638587403.

It is an arithmetic number, because the mean of its divisors is an integer number (2873417221323).

Almost surely, 2^{21620551613461} is an apocalyptic number.

It is an amenable number.

21620551613461 is a deficient number, since it is larger than the sum of its proper divisors (1366786157123).

21620551613461 is a wasteful number, since it uses less digits than its factorization.

21620551613461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5277166871.

The product of its (nonzero) digits is 259200, while the sum is 43.

The spelling of 21620551613461 in words is "twenty-one trillion, six hundred twenty billion, five hundred fifty-one million, six hundred thirteen thousand, four hundred sixty-one".