18765641961 has 12 divisors (see below), whose sum is σ = 29570102640. Its totient is φ = 11373116280.

The previous prime is 18765641957. The next prime is 18765641963. The reversal of 18765641961 is 16914656781.

18765641961 is a `hidden beast` number, since 1 + 8 + 7 + 6 + 564 + 19 + 61 = 666.

It is not a de Polignac number, because 18765641961 - 2² = 18765641957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18765641898 and 18765641907.

It is not an unprimeable number, because it can be changed into a prime (18765641963) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 94775871 + ... + 94776068.

It is an arithmetic number, because the mean of its divisors is an integer number (2464175220).

Almost surely, 2^18765641961 is an apocalyptic number.

18765641961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18765641961 is a deficient number, since it is larger than the sum of its proper divisors (10804460679).

18765641961 is a wasteful number, since it uses less digits than its factorization.

18765641961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189551956 (or 189551953 counting only the distinct ones).

The product of its digits is 2177280, while the sum is 54.

The spelling of 18765641961 in words is "eighteen billion, seven hundred sixty-five million, six hundred forty-one thousand, nine hundred sixty-one".