158821609 has 2 divisors, whose sum is σ = 158821610. Its totient is φ = 158821608.

The previous prime is 158821573. The next prime is 158821639. The reversal of 158821609 is 906128851.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 157251600 + 1570009 = 12540^2 + 1253^2 .

It is a cyclic number.

It is not a de Polignac number, because 158821609 - 2¹⁵ = 158788841 is a prime.

It is not a weakly prime, because it can be changed into another prime (158821639) 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, 79410804 + 79410805.

It is an arithmetic number, because the mean of its divisors is an integer number (79410805).

Almost surely, 2^158821609 is an apocalyptic number.

It is an amenable number.

158821609 is a deficient number, since it is larger than the sum of its proper divisors (1).

158821609 is an equidigital number, since it uses as much as digits as its factorization.

158821609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34560, while the sum is 40.

The square root of 158821609 is about 12602.4445644486. Note that the first 3 decimals coincide. The cubic root of 158821609 is about 541.5474690721.

The spelling of 158821609 in words is "one hundred fifty-eight million, eight hundred twenty-one thousand, six hundred nine".