21191613 has 8 divisors (see below), whose sum is σ = 28342176. Its totient is φ = 14084400.

The previous prime is 21191603. The next prime is 21191617. The reversal of 21191613 is 31619112.

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

It is not a de Polignac number, because 21191613 - 2⁵ = 21191581 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21191617) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9678 + ... + 11663.

It is an arithmetic number, because the mean of its divisors is an integer number (3542772).

Almost surely, 2^21191613 is an apocalyptic number.

It is an amenable number.

21191613 is a deficient number, since it is larger than the sum of its proper divisors (7150563).

21191613 is a wasteful number, since it uses less digits than its factorization.

21191613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21675.

The product of its digits is 324, while the sum is 24.

The square root of 21191613 is about 4603.4349131925. The cubic root of 21191613 is about 276.7289985524.

The spelling of 21191613 in words is "twenty-one million, one hundred ninety-one thousand, six hundred thirteen".