19997554815 has 192 divisors, whose sum is σ = 44349327360. Its totient is φ = 8124779520.

The previous prime is 19997554781. The next prime is 19997554817. The reversal of 19997554815 is 51845579991.

19997554815 is a `hidden beast` number, since 1 + 9 + 9 + 9 + 75 + 548 + 15 = 666.

It is not a de Polignac number, because 19997554815 - 2¹⁶ = 19997489279 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19997554817) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 7294345 + ... + 7297085.

It is an arithmetic number, because the mean of its divisors is an integer number (230986080).

Almost surely, 2^19997554815 is an apocalyptic number.

19997554815 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

19997554815 is an abundant number, since it is smaller than the sum of its proper divisors (24351772545).

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

19997554815 is a wasteful number, since it uses less digits than its factorization.

19997554815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2854 (or 2851 counting only the distinct ones).

The product of its digits is 20412000, while the sum is 63.

The spelling of 19997554815 in words is "nineteen billion, nine hundred ninety-seven million, five hundred fifty-four thousand, eight hundred fifteen".