21345939165 has 32 divisors (see below), whose sum is σ = 34384686336. Its totient is φ = 11307548160.

The previous prime is 21345939163. The next prime is 21345939217. The reversal of 21345939165 is 56193954312.

It is not a de Polignac number, because 21345939165 - 2¹ = 21345939163 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21345939163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4388835 + ... + 4393695.

It is an arithmetic number, because the mean of its divisors is an integer number (1074521448).

Almost surely, 2^21345939165 is an apocalyptic number.

It is an amenable number.

21345939165 is a deficient number, since it is larger than the sum of its proper divisors (13038747171).

21345939165 is a wasteful number, since it uses less digits than its factorization.

21345939165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6789.

The product of its digits is 874800, while the sum is 48.

The spelling of 21345939165 in words is "twenty-one billion, three hundred forty-five million, nine hundred thirty-nine thousand, one hundred sixty-five".