18931520478 has 32 divisors (see below), whose sum is σ = 42548438016. Its totient is φ = 5571818208.

The previous prime is 18931520473. The next prime is 18931520519. The reversal of 18931520478 is 87402513981.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18931520473) 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, 5274550 + ... + 5278137.

It is an arithmetic number, because the mean of its divisors is an integer number (1329638688).

Almost surely, 2^18931520478 is an apocalyptic number.

18931520478 is an abundant number, since it is smaller than the sum of its proper divisors (23616917538).

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

18931520478 is a wasteful number, since it uses less digits than its factorization.

18931520478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10552728.

The product of its (nonzero) digits is 483840, while the sum is 48.

The spelling of 18931520478 in words is "eighteen billion, nine hundred thirty-one million, five hundred twenty thousand, four hundred seventy-eight".