159921 has 8 divisors (see below), whose sum is σ = 236960. Its totient is φ = 106596.

The previous prime is 159911. The next prime is 159931. The reversal of 159921 is 129951.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (159911) and next prime (159931).

It is not a de Polignac number, because 159921 - 2⁶ = 159857 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 5923 = 159921 / (1 + 5 + 9 + 9 + 2 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (159911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2935 + ... + 2988.

It is an arithmetic number, because the mean of its divisors is an integer number (29620).

2¹⁵⁹⁹²¹ is an apocalyptic number.

It is an amenable number.

159921 is a deficient number, since it is larger than the sum of its proper divisors (77039).

159921 is an equidigital number, since it uses as much as digits as its factorization.

159921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5932 (or 5926 counting only the distinct ones).

The product of its digits is 810, while the sum is 27.

The square root of 159921 is about 399.9012378075. The cubic root of 159921 is about 54.2794159030.

The spelling of 159921 in words is "one hundred fifty-nine thousand, nine hundred twenty-one".