158545721 has 2 divisors, whose sum is σ = 158545722. Its totient is φ = 158545720.

The previous prime is 158545679. The next prime is 158545727. The reversal of 158545721 is 127545851.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129504400 + 29041321 = 11380^2 + 5389^2 .

It is a cyclic number.

It is not a de Polignac number, because 158545721 - 2¹⁸ = 158283577 is a prime.

It is equal to p_8897510 and since 158545721 and 8897510 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (158545727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79272860 + 79272861.

It is an arithmetic number, because the mean of its divisors is an integer number (79272861).

Almost surely, 2^158545721 is an apocalyptic number.

It is an amenable number.

158545721 is a deficient number, since it is larger than the sum of its proper divisors (1).

158545721 is an equidigital number, since it uses as much as digits as its factorization.

158545721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56000, while the sum is 38.

The square root of 158545721 is about 12591.4939939627. The cubic root of 158545721 is about 541.2337144479.

The spelling of 158545721 in words is "one hundred fifty-eight million, five hundred forty-five thousand, seven hundred twenty-one".