21911513 has 8 divisors (see below), whose sum is σ = 24358656. Its totient is φ = 19573200.

The previous prime is 21911509. The next prime is 21911573. The reversal of 21911513 is 31511912.

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 21911513 - 2² = 21911509 is a prime.

It is a super-2 number, since 2×21911513² = 960228803898338, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21911573) 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, 26783 + ... + 27588.

It is an arithmetic number, because the mean of its divisors is an integer number (3044832).

Almost surely, 2^21911513 is an apocalyptic number.

It is an amenable number.

21911513 is a deficient number, since it is larger than the sum of its proper divisors (2447143).

21911513 is a wasteful number, since it uses less digits than its factorization.

21911513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54415.

The product of its digits is 270, while the sum is 23.

The square root of 21911513 is about 4680.9735098588. The cubic root of 21911513 is about 279.8277554585.

The spelling of 21911513 in words is "twenty-one million, nine hundred eleven thousand, five hundred thirteen".