21361510621 has 16 divisors (see below), whose sum is σ = 23738083200. Its totient is φ = 19060715520.

The previous prime is 21361510619. The next prime is 21361510727. The reversal of 21361510621 is 12601516312.

It is not a de Polignac number, because 21361510621 - 2¹ = 21361510619 is a prime.

It is a super-2 number, since 2×21361510621² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21361510621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21361516621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44605 + ... + 211453.

It is an arithmetic number, because the mean of its divisors is an integer number (1483630200).

Almost surely, 2^21361510621 is an apocalyptic number.

It is an amenable number.

21361510621 is a deficient number, since it is larger than the sum of its proper divisors (2376572579).

21361510621 is a wasteful number, since it uses less digits than its factorization.

21361510621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167076.

The product of its (nonzero) digits is 2160, while the sum is 28.

The spelling of 21361510621 in words is "twenty-one billion, three hundred sixty-one million, five hundred ten thousand, six hundred twenty-one".