18240947961 has 4 divisors (see below), whose sum is σ = 24321263952. Its totient is φ = 12160631972.

The previous prime is 18240947953. The next prime is 18240947981. The reversal of 18240947961 is 16974904281.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18240947961 - 2³ = 18240947953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18240947951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3040157991 + ... + 3040157996.

It is an arithmetic number, because the mean of its divisors is an integer number (6080315988).

Almost surely, 2^18240947961 is an apocalyptic number.

It is an amenable number.

18240947961 is a deficient number, since it is larger than the sum of its proper divisors (6080315991).

18240947961 is an equidigital number, since it uses as much as digits as its factorization.

18240947961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6080315990.

The product of its (nonzero) digits is 870912, while the sum is 51.

The spelling of 18240947961 in words is "eighteen billion, two hundred forty million, nine hundred forty-seven thousand, nine hundred sixty-one".