18911275497 has 18 divisors (see below), whose sum is σ = 28365481898. Its totient is φ = 12607512624.

The previous prime is 18911275489. The next prime is 18911275501. The reversal of 18911275497 is 79457211981.

18911275497 is a `hidden beast` number, since 1 + 8 + 91 + 1 + 2 + 7 + 549 + 7 = 666.

It can be written as a sum of positive squares in only one way, i.e., 16461916416 + 2449359081 = 128304^2 + 49491^2 .

It is not a de Polignac number, because 18911275497 - 2³ = 18911275489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18911275997) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1434628 + ... + 1447749.

Almost surely, 2^18911275497 is an apocalyptic number.

It is an amenable number.

18911275497 is a deficient number, since it is larger than the sum of its proper divisors (9454206401).

18911275497 is an frugal number, since it uses more digits than its factorization.

18911275497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2882401 (or 2882380 counting only the distinct ones).

The product of its digits is 1270080, while the sum is 54.

The spelling of 18911275497 in words is "eighteen billion, nine hundred eleven million, two hundred seventy-five thousand, four hundred ninety-seven".