21036957 has 4 divisors (see below), whose sum is σ = 28049280. Its totient is φ = 14024636.

The previous prime is 21036947. The next prime is 21036959. The reversal of 21036957 is 75963012.

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 21036957 - 2¹⁵ = 21004189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036959) 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, 3506157 + ... + 3506162.

It is an arithmetic number, because the mean of its divisors is an integer number (7012320).

Almost surely, 2^21036957 is an apocalyptic number.

It is an amenable number.

21036957 is a deficient number, since it is larger than the sum of its proper divisors (7012323).

21036957 is an equidigital number, since it uses as much as digits as its factorization.

21036957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7012322.

The product of its (nonzero) digits is 11340, while the sum is 33.

The square root of 21036957 is about 4586.6062617146. The cubic root of 21036957 is about 276.0541665375.

Adding to 21036957 its reverse (75963012), we get a palindrome (96999969).

The spelling of 21036957 in words is "twenty-one million, thirty-six thousand, nine hundred fifty-seven".