18436509477 has 12 divisors (see below), whose sum is σ = 26632613644. Its totient is φ = 12290037120.

The previous prime is 18436509467. The next prime is 18436509493. The reversal of 18436509477 is 77490563481.

18436509477 is a `hidden beast` number, since 1 + 8 + 436 + 50 + 94 + 77 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13547563236 + 4888946241 = 116394^2 + 69921^2 .

It is not a de Polignac number, because 18436509477 - 2²³ = 18428120869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18436509407) 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, 51027 + ... + 198687.

Almost surely, 2^18436509477 is an apocalyptic number.

It is an amenable number.

18436509477 is a deficient number, since it is larger than the sum of its proper divisors (8196104167).

18436509477 is a wasteful number, since it uses less digits than its factorization.

18436509477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161540 (or 161537 counting only the distinct ones).

The product of its (nonzero) digits is 5080320, while the sum is 54.

The spelling of 18436509477 in words is "eighteen billion, four hundred thirty-six million, five hundred nine thousand, four hundred seventy-seven".