21165371439 has 8 divisors (see below), whose sum is σ = 28332928512. Its totient is φ = 14054031000.

The previous prime is 21165371419. The next prime is 21165371471. The reversal of 21165371439 is 93417356112.

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

It is not a de Polignac number, because 21165371439 - 2⁵ = 21165371407 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21165371439.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21165371419) 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, 14053279 + ... + 14054784.

It is an arithmetic number, because the mean of its divisors is an integer number (3541616064).

Almost surely, 2^21165371439 is an apocalyptic number.

21165371439 is a deficient number, since it is larger than the sum of its proper divisors (7167557073).

21165371439 is a wasteful number, since it uses less digits than its factorization.

21165371439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28108317.

The product of its digits is 136080, while the sum is 42.

The spelling of 21165371439 in words is "twenty-one billion, one hundred sixty-five million, three hundred seventy-one thousand, four hundred thirty-nine".