18916648621 has 4 divisors (see below), whose sum is σ = 20371775452. Its totient is φ = 17461521792.

The previous prime is 18916648591. The next prime is 18916648637. The reversal of 18916648621 is 12684661981.

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 9132669225 + 9783979396 = 95565^2 + 98914^2 .

It is not a de Polignac number, because 18916648621 - 2²⁷ = 18782430893 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 (18916048621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 727563396 + ... + 727563421.

It is an arithmetic number, because the mean of its divisors is an integer number (5092943863).

Almost surely, 2^18916648621 is an apocalyptic number.

It is an amenable number.

18916648621 is a deficient number, since it is larger than the sum of its proper divisors (1455126831).

18916648621 is a wasteful number, since it uses less digits than its factorization.

18916648621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1455126830.

The product of its digits is 995328, while the sum is 52.

The spelling of 18916648621 in words is "eighteen billion, nine hundred sixteen million, six hundred forty-eight thousand, six hundred twenty-one".