21010505239 has 8 divisors (see below), whose sum is σ = 21360125088. Its totient is φ = 20662377120.

The previous prime is 21010505213. The next prime is 21010505297. The reversal of 21010505239 is 93250501012.

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

It is a cyclic number.

It is not a de Polignac number, because 21010505239 - 2⁷ = 21010505111 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 (21010505039) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 344512 + ... + 400885.

It is an arithmetic number, because the mean of its divisors is an integer number (2670015636).

Almost surely, 2^21010505239 is an apocalyptic number.

21010505239 is a deficient number, since it is larger than the sum of its proper divisors (349619849).

21010505239 is an equidigital number, since it uses as much as digits as its factorization.

21010505239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 745865.

The product of its (nonzero) digits is 2700, while the sum is 28.

The spelling of 21010505239 in words is "twenty-one billion, ten million, five hundred five thousand, two hundred thirty-nine".