21380613 has 4 divisors (see below), whose sum is σ = 28507488. Its totient is φ = 14253740.

The previous prime is 21380603. The next prime is 21380621. The reversal of 21380613 is 31608312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21380613 - 2⁵ = 21380581 is a prime.

It is a super-2 number, since 2×21380613² = 914261224511538, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21380603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3563433 + ... + 3563438.

It is an arithmetic number, because the mean of its divisors is an integer number (7126872).

Almost surely, 2^21380613 is an apocalyptic number.

It is an amenable number.

21380613 is a deficient number, since it is larger than the sum of its proper divisors (7126875).

21380613 is an equidigital number, since it uses as much as digits as its factorization.

21380613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7126874.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 21380613 is about 4623.9174949387. The cubic root of 21380613 is about 277.5492453793.

Adding to 21380613 its reverse (31608312), we get a palindrome (52988925).

The spelling of 21380613 in words is "twenty-one million, three hundred eighty thousand, six hundred thirteen".