18978373440 has 448 divisors, whose sum is σ = 75904953600. Its totient is φ = 4425228288.

The previous prime is 18978373411. The next prime is 18978373471. The reversal of 18978373440 is 4437387981.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2129634 + ... + 2138526.

It is an arithmetic number, because the mean of its divisors is an integer number (169430700).

Almost surely, 2^18978373440 is an apocalyptic number.

18978373440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18978373440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37952476800).

18978373440 is an abundant number, since it is smaller than the sum of its proper divisors (56926580160).

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

18978373440 is a wasteful number, since it uses less digits than its factorization.

18978373440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8951 (or 8935 counting only the distinct ones).

The product of its (nonzero) digits is 4064256, while the sum is 54.

The spelling of 18978373440 in words is "eighteen billion, nine hundred seventy-eight million, three hundred seventy-three thousand, four hundred forty".