21902413 has 4 divisors (see below), whose sum is σ = 23587228. Its totient is φ = 20217600.

The previous prime is 21902411. The next prime is 21902429. The reversal of 21902413 is 31420912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5076009 + 16826404 = 2253^2 + 4102^2 .

It is not a de Polignac number, because 21902413 - 2¹ = 21902411 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 (21902411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 842388 + ... + 842413.

It is an arithmetic number, because the mean of its divisors is an integer number (5896807).

Almost surely, 2^21902413 is an apocalyptic number.

It is an amenable number.

21902413 is a deficient number, since it is larger than the sum of its proper divisors (1684815).

21902413 is a wasteful number, since it uses less digits than its factorization.

21902413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1684814.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21902413 is about 4680.0013888887. The cubic root of 21902413 is about 279.7890119728.

The spelling of 21902413 in words is "twenty-one million, nine hundred two thousand, four hundred thirteen".