15213540021 has 4 divisors (see below), whose sum is σ = 20284720032. Its totient is φ = 10142360012.

The previous prime is 15213540007. The next prime is 15213540061. The reversal of 15213540021 is 12004531251.

It is a happy number.

15213540021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 15213540021 - 2²⁵ = 15179985589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 15213539973 and 15213540000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15213540061) 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 3 ways as a sum of consecutive naturals, for example, 2535590001 + ... + 2535590006.

It is an arithmetic number, because the mean of its divisors is an integer number (5071180008).

Almost surely, 2^15213540021 is an apocalyptic number.

It is an amenable number.

15213540021 is a deficient number, since it is larger than the sum of its proper divisors (5071180011).

15213540021 is an equidigital number, since it uses as much as digits as its factorization.

15213540021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5071180010.

The product of its (nonzero) digits is 1200, while the sum is 24.

The spelling of 15213540021 in words is "fifteen billion, two hundred thirteen million, five hundred forty thousand, twenty-one".