18931023540 has 1440 divisors, whose sum is σ = 81757589760. Its totient is φ = 3613040640.

The previous prime is 18931023491. The next prime is 18931023719. The reversal of 18931023540 is 4532013981.

18931023540 is a `hidden beast` number, since 1 + 8 + 9 + 3 + 102 + 3 + 540 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18931023495 and 18931023504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 823087969 + ... + 823087991.

It is an arithmetic number, because the mean of its divisors is an integer number (56776104).

Almost surely, 2^18931023540 is an apocalyptic number.

18931023540 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 18931023540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40878794880).

18931023540 is an abundant number, since it is smaller than the sum of its proper divisors (62826566220).

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

18931023540 is a wasteful number, since it uses less digits than its factorization.

18931023540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 115 (or 93 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 18931023540 in words is "eighteen billion, nine hundred thirty-one million, twenty-three thousand, five hundred forty".