19815491136 has 56 divisors (see below), whose sum is σ = 59918274880. Its totient is φ = 5661568512.

The previous prime is 19815491027. The next prime is 19815491161. The reversal of 19815491136 is 63119451891.

It is a tau number, because it is divible by the number of its divisors (56).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7370491 + ... + 7373178.

Almost surely, 2^19815491136 is an apocalyptic number.

19815491136 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

19815491136 is an abundant number, since it is smaller than the sum of its proper divisors (40102783744).

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

19815491136 is a wasteful number, since it uses less digits than its factorization.

19815491136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14743691 (or 14743681 counting only the distinct ones).

The product of its digits is 233280, while the sum is 48.

The spelling of 19815491136 in words is "nineteen billion, eight hundred fifteen million, four hundred ninety-one thousand, one hundred thirty-six".