155735561 has 2 divisors, whose sum is σ = 155735562. Its totient is φ = 155735560.

The previous prime is 155735543. The next prime is 155735563. The reversal of 155735561 is 165537551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 116748025 + 38987536 = 10805^2 + 6244^2 .

It is a cyclic number.

It is not a de Polignac number, because 155735561 - 2⁶ = 155735497 is a prime.

Together with 155735563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (155735563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77867780 + 77867781.

It is an arithmetic number, because the mean of its divisors is an integer number (77867781).

Almost surely, 2^155735561 is an apocalyptic number.

It is an amenable number.

155735561 is a deficient number, since it is larger than the sum of its proper divisors (1).

155735561 is an equidigital number, since it uses as much as digits as its factorization.

155735561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 78750, while the sum is 38.

The square root of 155735561 is about 12479.4054746210. The cubic root of 155735561 is about 538.0169158089.

The spelling of 155735561 in words is "one hundred fifty-five million, seven hundred thirty-five thousand, five hundred sixty-one".