155920109 has 4 divisors (see below), whose sum is σ = 160134204. Its totient is φ = 151706016.

The previous prime is 155920091. The next prime is 155920123. The reversal of 155920109 is 901029551.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 63952009 + 91968100 = 7997^2 + 9590^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155920109 is a prime.

It is a super-2 number, since 2×155920109² = 48622160781143762, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155920129) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2106992 + ... + 2107065.

It is an arithmetic number, because the mean of its divisors is an integer number (40033551).

Almost surely, 2^155920109 is an apocalyptic number.

It is an amenable number.

155920109 is a deficient number, since it is larger than the sum of its proper divisors (4214095).

155920109 is an equidigital number, since it uses as much as digits as its factorization.

155920109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4214094.

The product of its (nonzero) digits is 4050, while the sum is 32.

The square root of 155920109 is about 12486.7973876411. The cubic root of 155920109 is about 538.2293501669.

The spelling of 155920109 in words is "one hundred fifty-five million, nine hundred twenty thousand, one hundred nine".