21120613 has 8 divisors (see below), whose sum is σ = 23134680. Its totient is φ = 19192320.

The previous prime is 21120607. The next prime is 21120629. The reversal of 21120613 is 31602112.

It can be written as a sum of positive squares in 4 ways, for example, as 10349089 + 10771524 = 3217^2 + 3282^2 .

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

It is not a de Polignac number, because 21120613 - 2⁵ = 21120581 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 (21120713) 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, 20928 + ... + 21913.

It is an arithmetic number, because the mean of its divisors is an integer number (2891835).

Almost surely, 2^21120613 is an apocalyptic number.

It is an amenable number.

21120613 is a deficient number, since it is larger than the sum of its proper divisors (2014067).

21120613 is a wasteful number, since it uses less digits than its factorization.

21120613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42887.

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

The square root of 21120613 is about 4595.7168102484. The cubic root of 21120613 is about 276.4196034735.

Adding to 21120613 its reverse (31602112), we get a palindrome (52722725).

The spelling of 21120613 in words is "twenty-one million, one hundred twenty thousand, six hundred thirteen".