18520913 has 2 divisors, whose sum is σ = 18520914. Its totient is φ = 18520912.

The previous prime is 18520907. The next prime is 18520921. The reversal of 18520913 is 31902581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13082689 + 5438224 = 3617^2 + 2332^2 .

It is a cyclic number.

It is not a de Polignac number, because 18520913 - 2²⁰ = 17472337 is a prime.

It is not a weakly prime, because it can be changed into another prime (18520933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9260456 + 9260457.

It is an arithmetic number, because the mean of its divisors is an integer number (9260457).

Almost surely, 2^18520913 is an apocalyptic number.

It is an amenable number.

18520913 is a deficient number, since it is larger than the sum of its proper divisors (1).

18520913 is an equidigital number, since it uses as much as digits as its factorization.

18520913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 18520913 is about 4303.5930337336. The cubic root of 18520913 is about 264.5782445105.

The spelling of 18520913 in words is "eighteen million, five hundred twenty thousand, nine hundred thirteen".