21054013 has 4 divisors (see below), whose sum is σ = 21368320. Its totient is φ = 20739708.

The previous prime is 21053987. The next prime is 21054017. The reversal of 21054013 is 31045012.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21054013 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 (21054017) 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, 157053 + ... + 157186.

It is an arithmetic number, because the mean of its divisors is an integer number (5342080).

Almost surely, 2^21054013 is an apocalyptic number.

It is an amenable number.

21054013 is a deficient number, since it is larger than the sum of its proper divisors (314307).

21054013 is an equidigital number, since it uses as much as digits as its factorization.

21054013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314306.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21054013 is about 4588.4652118110. The cubic root of 21054013 is about 276.1287512786.

Adding to 21054013 its reverse (31045012), we get a palindrome (52099025).

Subtracting 21054013 from its reverse (31045012), we obtain a palindrome (9990999).

The spelling of 21054013 in words is "twenty-one million, fifty-four thousand, thirteen".