21246413 has 6 divisors (see below), whose sum is σ = 22570026. Its totient is φ = 19996352.

The previous prime is 21246409. The next prime is 21246419. The reversal of 21246413 is 31464212.

It can be written as a sum of positive squares in 3 ways, for example, as 14160169 + 7086244 = 3763^2 + 2662^2 .

It is not a de Polignac number, because 21246413 - 2² = 21246409 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 (21246419) 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 5 ways as a sum of consecutive naturals, for example, 36470 + ... + 37047.

It is an arithmetic number, because the mean of its divisors is an integer number (3761671).

Almost surely, 2^21246413 is an apocalyptic number.

It is an amenable number.

21246413 is a deficient number, since it is larger than the sum of its proper divisors (1323613).

21246413 is an equidigital number, since it uses as much as digits as its factorization.

21246413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73551 (or 73534 counting only the distinct ones).

The product of its digits is 1152, while the sum is 23.

The square root of 21246413 is about 4609.3831474504. The cubic root of 21246413 is about 276.9673270555.

The spelling of 21246413 in words is "twenty-one million, two hundred forty-six thousand, four hundred thirteen".