21190913 has 4 divisors (see below), whose sum is σ = 21297600. Its totient is φ = 21084228.

The previous prime is 21190907. The next prime is 21190919. The reversal of 21190913 is 31909112.

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 an interprime number because it is at equal distance from previous prime (21190907) and next prime (21190919).

It is a cyclic number.

It is not a de Polignac number, because 21190913 - 2¹² = 21186817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21190919) 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, 53045 + ... + 53442.

It is an arithmetic number, because the mean of its divisors is an integer number (5324400).

Almost surely, 2^21190913 is an apocalyptic number.

It is an amenable number.

21190913 is a deficient number, since it is larger than the sum of its proper divisors (106687).

21190913 is a wasteful number, since it uses less digits than its factorization.

21190913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106686.

The product of its (nonzero) digits is 486, while the sum is 26.

The square root of 21190913 is about 4603.3588823814. The cubic root of 21190913 is about 276.7259515540.

The spelling of 21190913 in words is "twenty-one million, one hundred ninety thousand, nine hundred thirteen".