18681515977633 has 2 divisors, whose sum is σ = 18681515977634. Its totient is φ = 18681515977632.

The previous prime is 18681515977573. The next prime is 18681515977661. The reversal of 18681515977633 is 33677951518681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16573627229184 + 2107888748449 = 4071072^2 + 1451857^2 .

It is a cyclic number.

It is not a de Polignac number, because 18681515977633 - 2²¹ = 18681513880481 is a prime.

It is not a weakly prime, because it can be changed into another prime (18681515977433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9340757988816 + 9340757988817.

It is an arithmetic number, because the mean of its divisors is an integer number (9340757988817).

Almost surely, 2^{18681515977633} is an apocalyptic number.

It is an amenable number.

18681515977633 is a deficient number, since it is larger than the sum of its proper divisors (1).

18681515977633 is an equidigital number, since it uses as much as digits as its factorization.

18681515977633 is an evil number, because the sum of its binary digits is even.

The product of its digits is 228614400, while the sum is 70.

The spelling of 18681515977633 in words is "eighteen trillion, six hundred eighty-one billion, five hundred fifteen million, nine hundred seventy-seven thousand, six hundred thirty-three".