18998738440 has 64 divisors (see below), whose sum is σ = 47223648000. Its totient is φ = 6821168640.

The previous prime is 18998738431. The next prime is 18998738449. The reversal of 18998738440 is 4483789981.

It is an interprime number because it is at equal distance from previous prime (18998738431) and next prime (18998738449).

It is not an unprimeable number, because it can be changed into a prime (18998738449) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 238525 + ... + 308044.

It is an arithmetic number, because the mean of its divisors is an integer number (737869500).

Almost surely, 2^18998738440 is an apocalyptic number.

18998738440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18998738440 is an abundant number, since it is smaller than the sum of its proper divisors (28224909560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18998738440 is a wasteful number, since it uses less digits than its factorization.

18998738440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546670 (or 546666 counting only the distinct ones).

The product of its (nonzero) digits is 13934592, while the sum is 61.

The spelling of 18998738440 in words is "eighteen billion, nine hundred ninety-eight million, seven hundred thirty-eight thousand, four hundred forty".