21311413 has 2 divisors, whose sum is σ = 21311414. Its totient is φ = 21311412.

The previous prime is 21311399. The next prime is 21311417. The reversal of 21311413 is 31411312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19731364 + 1580049 = 4442^2 + 1257^2 .

It is a cyclic number.

It is not a de Polignac number, because 21311413 - 2⁹ = 21310901 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21311417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655706 + 10655707.

It is an arithmetic number, because the mean of its divisors is an integer number (10655707).

Almost surely, 2^21311413 is an apocalyptic number.

It is an amenable number.

21311413 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311413 is an equidigital number, since it uses as much as digits as its factorization.

21311413 is an evil number, because the sum of its binary digits is even.

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

The square root of 21311413 is about 4616.4285979532. The cubic root of 21311413 is about 277.2494852473.

Adding to 21311413 its reverse (31411312), we get a palindrome (52722725).

It can be divided in two parts, 2131 and 1413, that multiplied together give a palindrome (3011103).

The spelling of 21311413 in words is "twenty-one million, three hundred eleven thousand, four hundred thirteen".