21779013 has 12 divisors (see below), whose sum is σ = 29537664. Its totient is φ = 14274000.

The previous prime is 21779011. The next prime is 21779033. The reversal of 21779013 is 31097712.

It is not a de Polignac number, because 21779013 - 2¹ = 21779011 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21779011) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10188 + ... + 12138.

It is an arithmetic number, because the mean of its divisors is an integer number (2461472).

Almost surely, 2^21779013 is an apocalyptic number.

It is an amenable number.

21779013 is a deficient number, since it is larger than the sum of its proper divisors (7758651).

21779013 is an equidigital number, since it uses as much as digits as its factorization.

21779013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2076 (or 2015 counting only the distinct ones).

The product of its (nonzero) digits is 2646, while the sum is 30.

The square root of 21779013 is about 4666.7990100282. The cubic root of 21779013 is about 279.2625706090.

The spelling of 21779013 in words is "twenty-one million, seven hundred seventy-nine thousand, thirteen".