21386502165 has 32 divisors (see below), whose sum is σ = 39142932480. Its totient is φ = 9767640384.

The previous prime is 21386502121. The next prime is 21386502169. The reversal of 21386502165 is 56120568312.

It is not a de Polignac number, because 21386502165 - 2⁸ = 21386501909 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21386502169) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20446 + ... + 207824.

It is an arithmetic number, because the mean of its divisors is an integer number (1223216640).

Almost surely, 2^21386502165 is an apocalyptic number.

It is an amenable number.

21386502165 is a deficient number, since it is larger than the sum of its proper divisors (17756430315).

21386502165 is a wasteful number, since it uses less digits than its factorization.

21386502165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188481.

The product of its (nonzero) digits is 86400, while the sum is 39.

The spelling of 21386502165 in words is "twenty-one billion, three hundred eighty-six million, five hundred two thousand, one hundred sixty-five".