21107513 has 8 divisors (see below), whose sum is σ = 24188928. Its totient is φ = 18042624.

The previous prime is 21107509. The next prime is 21107531. The reversal of 21107513 is 31570112.

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 21107513 - 2² = 21107509 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21107543) 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, 1256 + ... + 6617.

It is an arithmetic number, because the mean of its divisors is an integer number (3023616).

Almost surely, 2^21107513 is an apocalyptic number.

It is an amenable number.

21107513 is a deficient number, since it is larger than the sum of its proper divisors (3081415).

21107513 is an equidigital number, since it uses as much as digits as its factorization.

21107513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8263.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 21107513 is about 4594.2913490548. The cubic root of 21107513 is about 276.3624421635.

Adding to 21107513 its reverse (31570112), we get a palindrome (52677625).

The spelling of 21107513 in words is "twenty-one million, one hundred seven thousand, five hundred thirteen".