18980813 has 2 divisors, whose sum is σ = 18980814. Its totient is φ = 18980812.

The previous prime is 18980807. The next prime is 18980839. The reversal of 18980813 is 31808981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17123044 + 1857769 = 4138^2 + 1363^2 .

It is a cyclic number.

It is not a de Polignac number, because 18980813 - 2⁶ = 18980749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18980893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9490406 + 9490407.

It is an arithmetic number, because the mean of its divisors is an integer number (9490407).

Almost surely, 2^18980813 is an apocalyptic number.

It is an amenable number.

18980813 is a deficient number, since it is larger than the sum of its proper divisors (1).

18980813 is an equidigital number, since it uses as much as digits as its factorization.

18980813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 38.

The square root of 18980813 is about 4356.6974877767. The cubic root of 18980813 is about 266.7503124752.

The spelling of 18980813 in words is "eighteen million, nine hundred eighty thousand, eight hundred thirteen".