19917157680 has 240 divisors, whose sum is σ = 77413140480. Its totient is φ = 4494776832.

The previous prime is 19917157661. The next prime is 19917157693. The reversal of 19917157680 is 8675171991.

It is a tau number, because it is divible by the number of its divisors (240).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 373149 + ... + 423171.

It is an arithmetic number, because the mean of its divisors is an integer number (322554752).

Almost surely, 2^19917157680 is an apocalyptic number.

19917157680 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 19917157680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38706570240).

19917157680 is an abundant number, since it is smaller than the sum of its proper divisors (57495982800).

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

19917157680 is a wasteful number, since it uses less digits than its factorization.

19917157680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50128 (or 50119 counting only the distinct ones).

The product of its (nonzero) digits is 952560, while the sum is 54.

The spelling of 19917157680 in words is "nineteen billion, nine hundred seventeen million, one hundred fifty-seven thousand, six hundred eighty".