21055413 has 4 divisors (see below), whose sum is σ = 28073888. Its totient is φ = 14036940.

The previous prime is 21055409. The next prime is 21055429. The reversal of 21055413 is 31455012.

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 not a de Polignac number, because 21055413 - 2² = 21055409 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21055413.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21055453) 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, 3509233 + ... + 3509238.

It is an arithmetic number, because the mean of its divisors is an integer number (7018472).

Almost surely, 2^21055413 is an apocalyptic number.

It is an amenable number.

21055413 is a deficient number, since it is larger than the sum of its proper divisors (7018475).

21055413 is an equidigital number, since it uses as much as digits as its factorization.

21055413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7018474.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 21055413 is about 4588.6177657329. The cubic root of 21055413 is about 276.1348715953.

The spelling of 21055413 in words is "twenty-one million, fifty-five thousand, four hundred thirteen".