21086357 has 4 divisors (see below), whose sum is σ = 21134400. Its totient is φ = 21038316.

The previous prime is 21086347. The next prime is 21086381. The reversal of 21086357 is 75368012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21086357 - 2¹⁸ = 20824213 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 (21086327) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23357 + ... + 24242.

It is an arithmetic number, because the mean of its divisors is an integer number (5283600).

Almost surely, 2^21086357 is an apocalyptic number.

It is an amenable number.

21086357 is a deficient number, since it is larger than the sum of its proper divisors (48043).

21086357 is an equidigital number, since it uses as much as digits as its factorization.

21086357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48042.

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

The square root of 21086357 is about 4591.9883492884. The cubic root of 21086357 is about 276.2700788692.

The spelling of 21086357 in words is "twenty-one million, eighty-six thousand, three hundred fifty-seven".