18491510961 has 192 divisors, whose sum is σ = 36781056000. Its totient is φ = 8661219840.

The previous prime is 18491510959. The next prime is 18491510969. The reversal of 18491510961 is 16901519481.

18491510961 is a `hidden beast` number, since 1 + 8 + 49 + 1 + 510 + 96 + 1 = 666.

It is not a de Polignac number, because 18491510961 - 2¹ = 18491510959 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18491510969) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 30165291 + ... + 30165903.

It is an arithmetic number, because the mean of its divisors is an integer number (191568000).

Almost surely, 2^18491510961 is an apocalyptic number.

18491510961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18491510961 is a deficient number, since it is larger than the sum of its proper divisors (18289545039).

18491510961 is a wasteful number, since it uses less digits than its factorization.

18491510961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 764 (or 761 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 45.

The spelling of 18491510961 in words is "eighteen billion, four hundred ninety-one million, five hundred ten thousand, nine hundred sixty-one".