159721921601 has 72 divisors (see below), whose sum is σ = 194028912000. Its totient is φ = 131196567040.

The previous prime is 159721921561. The next prime is 159721921603. The reversal of 159721921601 is 106129127951.

It is not a de Polignac number, because 159721921601 - 2¹⁸ = 159721659457 is a prime.

It is a super-2 number, since 2×159721921601² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (159721921603) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 242369810 + ... + 242370468.

It is an arithmetic number, because the mean of its divisors is an integer number (2694846000).

Almost surely, 2^159721921601 is an apocalyptic number.

159721921601 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

159721921601 is a deficient number, since it is larger than the sum of its proper divisors (34306990399).

159721921601 is a wasteful number, since it uses less digits than its factorization.

159721921601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 983 (or 955 counting only the distinct ones).

The product of its (nonzero) digits is 68040, while the sum is 44.

The spelling of 159721921601 in words is "one hundred fifty-nine billion, seven hundred twenty-one million, nine hundred twenty-one thousand, six hundred one".