155639009 has 2 divisors, whose sum is σ = 155639010. Its totient is φ = 155639008.

The previous prime is 155638981. The next prime is 155639021. The reversal of 155639009 is 900936551.

155639009 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 96963409 + 58675600 = 9847^2 + 7660^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155639009 is a prime.

It is a super-2 number, since 2×155639009² = 48447002245004162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (155639039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77819504 + 77819505.

It is an arithmetic number, because the mean of its divisors is an integer number (77819505).

Almost surely, 2^155639009 is an apocalyptic number.

It is an amenable number.

155639009 is a deficient number, since it is larger than the sum of its proper divisors (1).

155639009 is an equidigital number, since it uses as much as digits as its factorization.

155639009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36450, while the sum is 38.

The square root of 155639009 is about 12475.5364213328. The cubic root of 155639009 is about 537.9057073223.

The spelling of 155639009 in words is "one hundred fifty-five million, six hundred thirty-nine thousand, nine".