19978177957920 has 960 divisors, whose sum is σ = 88893736436736. Its totient is φ = 4112356884480.

The previous prime is 19978177957901. The next prime is 19978177957943. The reversal of 19978177957920 is 2975977187991.

19978177957920 is a `hidden beast` number, since 1 + 9 + 9 + 7 + 8 + 17 + 7 + 9 + 579 + 20 = 666.

It is a super-3 number, since 3×19978177957920³ (a number of 41 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a self number, because there is not a number n which added to its sum of digits gives 19978177957920.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 48147177 + ... + 48560343.

Almost surely, 2^{19978177957920} is an apocalyptic number.

19978177957920 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 19978177957920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44446868218368).

19978177957920 is an abundant number, since it is smaller than the sum of its proper divisors (68915558478816).

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

19978177957920 is a wasteful number, since it uses less digits than its factorization.

19978177957920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 413255 (or 413238 counting only the distinct ones).

The product of its (nonzero) digits is 1260236880, while the sum is 81.

The spelling of 19978177957920 in words is "nineteen trillion, nine hundred seventy-eight billion, one hundred seventy-seven million, nine hundred fifty-seven thousand, nine hundred twenty".