158721 has 8 divisors (see below), whose sum is σ = 213504. Its totient is φ = 104880.

The previous prime is 158699. The next prime is 158731. The reversal of 158721 is 127851.

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

It is not a de Polignac number, because 158721 - 2⁶ = 158657 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 158691 and 158700.

It is not an unprimeable number, because it can be changed into a prime (158731) 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, 435 + ... + 711.

It is an arithmetic number, because the mean of its divisors is an integer number (26688).

It is a Proth number, since it is equal to 155 ⋅ 2¹⁰ + 1 and 155 < 2¹⁰.

2¹⁵⁸⁷²¹ is an apocalyptic number.

It is an amenable number.

158721 is a deficient number, since it is larger than the sum of its proper divisors (54783).

158721 is a wasteful number, since it uses less digits than its factorization.

158721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471.

The product of its digits is 560, while the sum is 24.

The square root of 158721 is about 398.3980421639. The cubic root of 158721 is about 54.1433093246.

The spelling of 158721 in words is "one hundred fifty-eight thousand, seven hundred twenty-one".