21375391593 has 4 divisors (see below), whose sum is σ = 28500522128. Its totient is φ = 14250261060.

The previous prime is 21375391579. The next prime is 21375391613. The reversal of 21375391593 is 39519357312.

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 21375391593 - 2¹² = 21375387497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21375391523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3562565263 + ... + 3562565268.

It is an arithmetic number, because the mean of its divisors is an integer number (7125130532).

Almost surely, 2^21375391593 is an apocalyptic number.

It is an amenable number.

21375391593 is a deficient number, since it is larger than the sum of its proper divisors (7125130535).

21375391593 is an equidigital number, since it uses as much as digits as its factorization.

21375391593 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7125130534.

The product of its digits is 765450, while the sum is 48.

The spelling of 21375391593 in words is "twenty-one billion, three hundred seventy-five million, three hundred ninety-one thousand, five hundred ninety-three".