19971159768 has 640 divisors, whose sum is σ = 73138982400. Its totient is φ = 4953747456.

The previous prime is 19971159757. The next prime is 19971159779. The reversal of 19971159768 is 86795117991.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (19971159757) and next prime (19971159779).

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

It is a congruent number.

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, 63000346 + ... + 63000662.

It is an arithmetic number, because the mean of its divisors is an integer number (114279660).

Almost surely, 2^19971159768 is an apocalyptic number.

19971159768 is a gapful number since it is divisible by the number (18) 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 19971159768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36569491200).

19971159768 is an abundant number, since it is smaller than the sum of its proper divisors (53167822632).

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

19971159768 is a wasteful number, since it uses less digits than its factorization.

19971159768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421 (or 408 counting only the distinct ones).

The product of its digits is 8573040, while the sum is 63.

The spelling of 19971159768 in words is "nineteen billion, nine hundred seventy-one million, one hundred fifty-nine thousand, seven hundred sixty-eight".