18640713961 has 3 divisors (see below), whose sum is σ = 18640850493. Its totient is φ = 18640577430.

The previous prime is 18640713953. The next prime is 18640713967. The reversal of 18640713961 is 16931704681.

The square root of 18640713961 is 136531.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 16931704681 = 4723 ⋅3584947.

It is not a de Polignac number, because 18640713961 - 2³ = 18640713953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18640713967) 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 2 ways as a sum of consecutive naturals, for example, 68266 + ... + 204796.

It is an arithmetic number, because the mean of its divisors is an integer number (6213616831).

Almost surely, 2^18640713961 is an apocalyptic number.

18640713961 is the 136531-st square number.

18640713961 is the 68266-th centered octagonal number.

It is an amenable number.

18640713961 is a deficient number, since it is larger than the sum of its proper divisors (136532).

18640713961 is an frugal number, since it uses more digits than its factorization.

18640713961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273062 (or 136531 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 46.

The spelling of 18640713961 in words is "eighteen billion, six hundred forty million, seven hundred thirteen thousand, nine hundred sixty-one".