18554001556 has 6 divisors (see below), whose sum is σ = 32469502730. Its totient is φ = 9277000776.

The previous prime is 18554001551. The next prime is 18554001593. The reversal of 18554001556 is 65510045581.

It can be written as a sum of positive squares in only one way, i.e., 11000653456 + 7553348100 = 104884^2 + 86910^2 .

It is a super-2 number, since 2×18554001556² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18554001551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2319250191 + ... + 2319250198.

Almost surely, 2^18554001556 is an apocalyptic number.

It is an amenable number.

18554001556 is a deficient number, since it is larger than the sum of its proper divisors (13915501174).

18554001556 is a wasteful number, since it uses less digits than its factorization.

18554001556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4638500393 (or 4638500391 counting only the distinct ones).

The product of its (nonzero) digits is 120000, while the sum is 40.

The spelling of 18554001556 in words is "eighteen billion, five hundred fifty-four million, one thousand, five hundred fifty-six".