87905561 has 2 divisors, whose sum is σ = 87905562. Its totient is φ = 87905560.

The previous prime is 87905551. The next prime is 87905569. The reversal of 87905561 is 16550978.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 85747600 + 2157961 = 9260^2 + 1469^2 .

It is a cyclic number.

It is not a de Polignac number, because 87905561 - 2⁶ = 87905497 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (87905569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43952780 + 43952781.

It is an arithmetic number, because the mean of its divisors is an integer number (43952781).

Almost surely, 2^87905561 is an apocalyptic number.

It is an amenable number.

87905561 is a deficient number, since it is larger than the sum of its proper divisors (1).

87905561 is an equidigital number, since it uses as much as digits as its factorization.

87905561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 75600, while the sum is 41.

The square root of 87905561 is about 9375.7965528269. The cubic root of 87905561 is about 444.6368471794.

The spelling of 87905561 in words is "eighty-seven million, nine hundred five thousand, five hundred sixty-one".