90155308561 has 2 divisors, whose sum is σ = 90155308562. Its totient is φ = 90155308560.

The previous prime is 90155308559. The next prime is 90155308577. The reversal of 90155308561 is 16580355109.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 46329979536 + 43825329025 = 215244^2 + 209345^2 .

It is a cyclic number.

It is not a de Polignac number, because 90155308561 - 2¹ = 90155308559 is a prime.

Together with 90155308559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (90155408561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45077654280 + 45077654281.

It is an arithmetic number, because the mean of its divisors is an integer number (45077654281).

Almost surely, 2^90155308561 is an apocalyptic number.

It is an amenable number.

90155308561 is a deficient number, since it is larger than the sum of its proper divisors (1).

90155308561 is an equidigital number, since it uses as much as digits as its factorization.

90155308561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162000, while the sum is 43.

The spelling of 90155308561 in words is "ninety billion, one hundred fifty-five million, three hundred eight thousand, five hundred sixty-one".