21386351 has 16 divisors (see below), whose sum is σ = 25200384. Its totient is φ = 17769024.

The previous prime is 21386347. The next prime is 21386353. The reversal of 21386351 is 15368312.

It is not a de Polignac number, because 21386351 - 2² = 21386347 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 (21386353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68171 + ... + 68483.

It is an arithmetic number, because the mean of its divisors is an integer number (1575024).

Almost surely, 2^21386351 is an apocalyptic number.

21386351 is a deficient number, since it is larger than the sum of its proper divisors (3814033).

21386351 is a wasteful number, since it uses less digits than its factorization.

21386351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 590.

The product of its digits is 4320, while the sum is 29.

The square root of 21386351 is about 4624.5379228632. The cubic root of 21386351 is about 277.5740721562.

The spelling of 21386351 in words is "twenty-one million, three hundred eighty-six thousand, three hundred fifty-one".