21150413356521 has 4 divisors (see below), whose sum is σ = 28200551142032. Its totient is φ = 14100275571012.

The previous prime is 21150413356487. The next prime is 21150413356547. The reversal of 21150413356521 is 12565331405112.

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 not a de Polignac number, because 21150413356521 - 2²² = 21150409162217 is a prime.

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 21150413356521.

It is not an unprimeable number, because it can be changed into a prime (21150413356561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3525068892751 + ... + 3525068892756.

It is an arithmetic number, because the mean of its divisors is an integer number (7050137785508).

Almost surely, 2^{21150413356521} is an apocalyptic number.

It is an amenable number.

21150413356521 is a deficient number, since it is larger than the sum of its proper divisors (7050137785511).

21150413356521 is an equidigital number, since it uses as much as digits as its factorization.

21150413356521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7050137785510.

The product of its (nonzero) digits is 108000, while the sum is 39.

The spelling of 21150413356521 in words is "twenty-one trillion, one hundred fifty billion, four hundred thirteen million, three hundred fifty-six thousand, five hundred twenty-one".