21520012535 has 8 divisors (see below), whose sum is σ = 29513160096. Its totient is φ = 14756580000.

The previous prime is 21520012511. The next prime is 21520012559. The reversal of 21520012535 is 53521002512.

It is an interprime number because it is at equal distance from previous prime (21520012511) and next prime (21520012559).

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

It is not a de Polignac number, because 21520012535 - 2¹⁶ = 21519946999 is a prime.

It is a super-2 number, since 2×21520012535² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 307428716 + ... + 307428785.

It is an arithmetic number, because the mean of its divisors is an integer number (3689145012).

Almost surely, 2^21520012535 is an apocalyptic number.

21520012535 is a deficient number, since it is larger than the sum of its proper divisors (7993147561).

21520012535 is an equidigital number, since it uses as much as digits as its factorization.

21520012535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 614857513.

The product of its (nonzero) digits is 3000, while the sum is 26.

The spelling of 21520012535 in words is "twenty-one billion, five hundred twenty million, twelve thousand, five hundred thirty-five".