21211313 has 12 divisors (see below), whose sum is σ = 22449588. Its totient is φ = 20037600.

The previous prime is 21211259. The next prime is 21211319. The reversal of 21211313 is 31311212.

It can be written as a sum of positive squares in 2 ways, for example, as 17909824 + 3301489 = 4232^2 + 1817^2 .

It is not a de Polignac number, because 21211313 - 2²⁴ = 4434097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21211319) 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 11 ways as a sum of consecutive naturals, for example, 53231 + ... + 53627.

It is an arithmetic number, because the mean of its divisors is an integer number (1870799).

Almost surely, 2^21211313 is an apocalyptic number.

21211313 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21211313 is a deficient number, since it is larger than the sum of its proper divisors (1238275).

21211313 is a wasteful number, since it uses less digits than its factorization.

21211313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544 (or 521 counting only the distinct ones).

The product of its digits is 36, while the sum is 14.

The square root of 21211313 is about 4605.5741227343. The cubic root of 21211313 is about 276.8147222907.

Adding to 21211313 its reverse (31311212), we get a palindrome (52522525).

The spelling of 21211313 in words is "twenty-one million, two hundred eleven thousand, three hundred thirteen".