155447561 has 2 divisors, whose sum is σ = 155447562. Its totient is φ = 155447560.

The previous prime is 155447533. The next prime is 155447599. The reversal of 155447561 is 165744551.

It is an a-pointer prime, because the next prime (155447599) can be obtained adding 155447561 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152275600 + 3171961 = 12340^2 + 1781^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155447561 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (155447161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77723780 + 77723781.

It is an arithmetic number, because the mean of its divisors is an integer number (77723781).

Almost surely, 2^155447561 is an apocalyptic number.

It is an amenable number.

155447561 is a deficient number, since it is larger than the sum of its proper divisors (1).

155447561 is an equidigital number, since it uses as much as digits as its factorization.

155447561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84000, while the sum is 38.

The square root of 155447561 is about 12467.8611237052. The cubic root of 155447561 is about 537.6850616409.

The spelling of 155447561 in words is "one hundred fifty-five million, four hundred forty-seven thousand, five hundred sixty-one".