155239681 has 2 divisors, whose sum is σ = 155239682. Its totient is φ = 155239680.

The previous prime is 155239607. The next prime is 155239717. The reversal of 155239681 is 186932551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 147841281 + 7398400 = 12159^2 + 2720^2 .

It is a cyclic number.

It is not a de Polignac number, because 155239681 - 2²¹ = 153142529 is a prime.

It is a super-2 number, since 2×155239681² = 48198717113963522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (155239181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77619840 + 77619841.

It is an arithmetic number, because the mean of its divisors is an integer number (77619841).

Almost surely, 2^155239681 is an apocalyptic number.

It is an amenable number.

155239681 is a deficient number, since it is larger than the sum of its proper divisors (1).

155239681 is an equidigital number, since it uses as much as digits as its factorization.

155239681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64800, while the sum is 40.

The square root of 155239681 is about 12459.5217002901. The cubic root of 155239681 is about 537.4452726684.

The spelling of 155239681 in words is "one hundred fifty-five million, two hundred thirty-nine thousand, six hundred eighty-one".