159721957 has 8 divisors (see below), whose sum is σ = 160671896. Its totient is φ = 158775552.

The previous prime is 159721943. The next prime is 159721979. The reversal of 159721957 is 759127951.

It can be written as a sum of positive squares in 4 ways, for example, as 17969121 + 141752836 = 4239^2 + 11906^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 159721957 - 2⁷ = 159721829 is a prime.

It is a super-2 number, since 2×159721957² = 51022207095819698, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (159721157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 169993 + ... + 170929.

It is an arithmetic number, because the mean of its divisors is an integer number (20083987).

Almost surely, 2^159721957 is an apocalyptic number.

It is an amenable number.

159721957 is a deficient number, since it is larger than the sum of its proper divisors (949939).

159721957 is an equidigital number, since it uses as much as digits as its factorization.

159721957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1767.

The product of its digits is 198450, while the sum is 46.

The square root of 159721957 is about 12638.1152471403. The cubic root of 159721957 is about 542.5688723111.

The spelling of 159721957 in words is "one hundred fifty-nine million, seven hundred twenty-one thousand, nine hundred fifty-seven".