159994721 has 4 divisors (see below), whose sum is σ = 163398912. Its totient is φ = 156590532.

The previous prime is 159994717. The next prime is 159994729. The reversal of 159994721 is 127499951.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 159994721 - 2² = 159994717 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (47), and also a Moran number because the ratio is a prime number: 3404143 = 159994721 / (1 + 5 + 9 + 9 + 9 + 4 + 7 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (159994729) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1702025 + ... + 1702118.

It is an arithmetic number, because the mean of its divisors is an integer number (40849728).

Almost surely, 2^159994721 is an apocalyptic number.

It is an amenable number.

159994721 is a deficient number, since it is larger than the sum of its proper divisors (3404191).

159994721 is an equidigital number, since it uses as much as digits as its factorization.

159994721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3404190.

The product of its digits is 204120, while the sum is 47.

The square root of 159994721 is about 12648.9019681552. The cubic root of 159994721 is about 542.8775526656.

The spelling of 159994721 in words is "one hundred fifty-nine million, nine hundred ninety-four thousand, seven hundred twenty-one".