221979013 has 4 divisors (see below), whose sum is σ = 235036620. Its totient is φ = 208921408.

The previous prime is 221979011. The next prime is 221979031. The reversal of 221979013 is 310979122.

It is a happy number.

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 150356644 + 71622369 = 12262^2 + 8463^2 .

It is a cyclic number.

It is not a de Polignac number, because 221979013 - 2¹ = 221979011 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 221979013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221979011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6528778 + ... + 6528811.

It is an arithmetic number, because the mean of its divisors is an integer number (58759155).

Almost surely, 2^221979013 is an apocalyptic number.

It is an amenable number.

221979013 is a deficient number, since it is larger than the sum of its proper divisors (13057607).

221979013 is a wasteful number, since it uses less digits than its factorization.

221979013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13057606.

The product of its (nonzero) digits is 6804, while the sum is 34.

The square root of 221979013 is about 14898.9601314991. The cubic root of 221979013 is about 605.4858133723.

The spelling of 221979013 in words is "two hundred twenty-one million, nine hundred seventy-nine thousand, thirteen".