158721001 has 2 divisors, whose sum is σ = 158721002. Its totient is φ = 158721000.

The previous prime is 158720987. The next prime is 158721011. The reversal of 158721001 is 100127851.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 107226025 + 51494976 = 10355^2 + 7176^2 .

It is a cyclic number.

It is not a de Polignac number, because 158721001 - 2⁷ = 158720873 is a prime.

It is not a weakly prime, because it can be changed into another prime (158721011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79360500 + 79360501.

It is an arithmetic number, because the mean of its divisors is an integer number (79360501).

Almost surely, 2^158721001 is an apocalyptic number.

It is an amenable number.

158721001 is a deficient number, since it is larger than the sum of its proper divisors (1).

158721001 is an equidigital number, since it uses as much as digits as its factorization.

158721001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 560, while the sum is 25.

The square root of 158721001 is about 12598.4523255835. The cubic root of 158721001 is about 541.4330943831.

Adding to 158721001 its reverse (100127851), we get a palindrome (258848852).

The spelling of 158721001 in words is "one hundred fifty-eight million, seven hundred twenty-one thousand, one".