19785497856 has 36 divisors (see below), whose sum is σ = 52658280192. Its totient is φ = 6595165696.

The previous prime is 19785497819. The next prime is 19785497881. The reversal of 19785497856 is 65879458791.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12880416 + ... + 12881951.

Almost surely, 2^19785497856 is an apocalyptic number.

19785497856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

19785497856 is an abundant number, since it is smaller than the sum of its proper divisors (32872782336).

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

19785497856 is an equidigital number, since it uses as much as digits as its factorization.

19785497856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25762386 (or 25762372 counting only the distinct ones).

The product of its digits is 152409600, while the sum is 69.

The spelling of 19785497856 in words is "nineteen billion, seven hundred eighty-five million, four hundred ninety-seven thousand, eight hundred fifty-six".