21012613 has 8 divisors (see below), whose sum is σ = 22183200. Its totient is φ = 19848528.

The previous prime is 21012599. The next prime is 21012647. The reversal of 21012613 is 31621012.

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 21012613 - 2⁵ = 21012581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5970 + ... + 8812.

It is an arithmetic number, because the mean of its divisors is an integer number (2772900).

Almost surely, 2^21012613 is an apocalyptic number.

It is an amenable number.

21012613 is a deficient number, since it is larger than the sum of its proper divisors (1170587).

21012613 is a wasteful number, since it uses less digits than its factorization.

21012613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3251.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 21012613 is about 4583.9516795010. The cubic root of 21012613 is about 275.9476419970.

Adding to 21012613 its reverse (31621012), we get a palindrome (52633625).

The spelling of 21012613 in words is "twenty-one million, twelve thousand, six hundred thirteen".