157990109 has 2 divisors, whose sum is σ = 157990110. Its totient is φ = 157990108.

The previous prime is 157990069. The next prime is 157990121. The reversal of 157990109 is 901099751.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 116748025 + 41242084 = 10805^2 + 6422^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-157990109 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (157990169) 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, 78995054 + 78995055.

It is an arithmetic number, because the mean of its divisors is an integer number (78995055).

Almost surely, 2^157990109 is an apocalyptic number.

It is an amenable number.

157990109 is a deficient number, since it is larger than the sum of its proper divisors (1).

157990109 is an equidigital number, since it uses as much as digits as its factorization.

157990109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25515, while the sum is 41.

The square root of 157990109 is about 12569.4116409639. The cubic root of 157990109 is about 540.6007363407.

The spelling of 157990109 in words is "one hundred fifty-seven million, nine hundred ninety thousand, one hundred nine".