18708651961 has 2 divisors, whose sum is σ = 18708651962. Its totient is φ = 18708651960.

The previous prime is 18708651959. The next prime is 18708651971. The reversal of 18708651961 is 16915680781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14578147600 + 4130504361 = 120740^2 + 64269^2 .

It is a cyclic number.

It is not a de Polignac number, because 18708651961 - 2¹ = 18708651959 is a prime.

Together with 18708651959, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 18708651899 and 18708651908.

It is not a weakly prime, because it can be changed into another prime (18708651971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9354325980 + 9354325981.

It is an arithmetic number, because the mean of its divisors is an integer number (9354325981).

Almost surely, 2^18708651961 is an apocalyptic number.

It is an amenable number.

18708651961 is a deficient number, since it is larger than the sum of its proper divisors (1).

18708651961 is an equidigital number, since it uses as much as digits as its factorization.

18708651961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 725760, while the sum is 52.

The spelling of 18708651961 in words is "eighteen billion, seven hundred eight million, six hundred fifty-one thousand, nine hundred sixty-one".