87205561 has 2 divisors, whose sum is σ = 87205562. Its totient is φ = 87205560.

The previous prime is 87205553. The next prime is 87205579. The reversal of 87205561 is 16550278.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73188025 + 14017536 = 8555^2 + 3744^2 .

It is a cyclic number.

It is not a de Polignac number, because 87205561 - 2³ = 87205553 is a prime.

It is not a weakly prime, because it can be changed into another prime (87205861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43602780 + 43602781.

It is an arithmetic number, because the mean of its divisors is an integer number (43602781).

Almost surely, 2^87205561 is an apocalyptic number.

It is an amenable number.

87205561 is a deficient number, since it is larger than the sum of its proper divisors (1).

87205561 is an equidigital number, since it uses as much as digits as its factorization.

87205561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 87205561 is about 9338.3917780312. The cubic root of 87205561 is about 443.4534725692.

The spelling of 87205561 in words is "eighty-seven million, two hundred five thousand, five hundred sixty-one".