158115721 has 16 divisors (see below), whose sum is σ = 165989376. Its totient is φ = 150480000.

The previous prime is 158115707. The next prime is 158115757. The reversal of 158115721 is 127511851.

158115721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 158115721 - 2¹³ = 158107529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (158115781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 477526 + ... + 477856.

It is an arithmetic number, because the mean of its divisors is an integer number (10374336).

It is a Poulet number, since it divides 2^158115720-1.

Almost surely, 2^158115721 is an apocalyptic number.

It is an amenable number.

158115721 is a deficient number, since it is larger than the sum of its proper divisors (7873655).

158115721 is a wasteful number, since it uses less digits than its factorization.

158115721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 624.

The product of its digits is 2800, while the sum is 31.

The square root of 158115721 is about 12574.4073816622. The cubic root of 158115721 is about 540.7439688329.

The spelling of 158115721 in words is "one hundred fifty-eight million, one hundred fifteen thousand, seven hundred twenty-one".