21055013 has 8 divisors (see below), whose sum is σ = 24575232. Its totient is φ = 17662896.

The previous prime is 21055003. The next prime is 21055033. The reversal of 21055013 is 31055012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21055013 - 2⁸ = 21054757 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21054982 and 21055000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21055003) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31670 + ... + 32327.

It is an arithmetic number, because the mean of its divisors is an integer number (3071904).

Almost surely, 2^21055013 is an apocalyptic number.

It is an amenable number.

21055013 is a deficient number, since it is larger than the sum of its proper divisors (3520219).

21055013 is an equidigital number, since it uses as much as digits as its factorization.

21055013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64051.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 21055013 is about 4588.5741794156. The cubic root of 21055013 is about 276.1331229611.

Subtracting 21055013 from its reverse (31055012), we obtain a palindrome (9999999).

The spelling of 21055013 in words is "twenty-one million, fifty-five thousand, thirteen".