21525512413 has 4 divisors (see below), whose sum is σ = 21525823548. Its totient is φ = 21525201280.

The previous prime is 21525512383. The next prime is 21525512429. The reversal of 21525512413 is 31421552512.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 12951122809 + 8574389604 = 113803^2 + 92598^2 .

It is a cyclic number.

It is not a de Polignac number, because 21525512413 - 2⁵ = 21525512381 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 (21525512443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 195 + ... + 207487.

It is an arithmetic number, because the mean of its divisors is an integer number (5381455887).

Almost surely, 2^21525512413 is an apocalyptic number.

It is an amenable number.

21525512413 is a deficient number, since it is larger than the sum of its proper divisors (311135).

21525512413 is a wasteful number, since it uses less digits than its factorization.

21525512413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311134.

The product of its digits is 12000, while the sum is 31.

The spelling of 21525512413 in words is "twenty-one billion, five hundred twenty-five million, five hundred twelve thousand, four hundred thirteen".