21056357 has 8 divisors (see below), whose sum is σ = 24123456. Its totient is φ = 18004032.

The previous prime is 21056311. The next prime is 21056363. The reversal of 21056357 is 75365012.

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 21056357 - 2¹² = 21052261 is a prime.

It is a super-2 number, since 2×21056357² = 886740340222898, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21050357) 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, 443 + ... + 6504.

It is an arithmetic number, because the mean of its divisors is an integer number (3015432).

Almost surely, 2^21056357 is an apocalyptic number.

It is an amenable number.

21056357 is a deficient number, since it is larger than the sum of its proper divisors (3067099).

21056357 is an equidigital number, since it uses as much as digits as its factorization.

21056357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7387.

The product of its (nonzero) digits is 6300, while the sum is 29.

The square root of 21056357 is about 4588.7206278003. The cubic root of 21056357 is about 276.1389982843.

The spelling of 21056357 in words is "twenty-one million, fifty-six thousand, three hundred fifty-seven".