21386507 has 8 divisors (see below), whose sum is σ = 21885120. Its totient is φ = 20891520.

The previous prime is 21386503. The next prime is 21386531. The reversal of 21386507 is 70568312.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21386507 - 2² = 21386503 is a prime.

It is a super-2 number, since 2×21386507² = 914765363322098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21386501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13619 + ... + 15107.

It is an arithmetic number, because the mean of its divisors is an integer number (2735640).

Almost surely, 2^21386507 is an apocalyptic number.

21386507 is a deficient number, since it is larger than the sum of its proper divisors (498613).

21386507 is a wasteful number, since it uses less digits than its factorization.

21386507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1813.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21386507 is about 4624.5547893824. The cubic root of 21386507 is about 277.5747470640.

The spelling of 21386507 in words is "twenty-one million, three hundred eighty-six thousand, five hundred seven".