87790561 has 2 divisors, whose sum is σ = 87790562. Its totient is φ = 87790560.

The previous prime is 87790531. The next prime is 87790597. The reversal of 87790561 is 16509778.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 85673536 + 2117025 = 9256^2 + 1455^2 .

It is a cyclic number.

It is not a de Polignac number, because 87790561 - 2⁹ = 87790049 is a prime.

It is not a weakly prime, because it can be changed into another prime (87790531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43895280 + 43895281.

It is an arithmetic number, because the mean of its divisors is an integer number (43895281).

Almost surely, 2^87790561 is an apocalyptic number.

It is an amenable number.

87790561 is a deficient number, since it is larger than the sum of its proper divisors (1).

87790561 is an equidigital number, since it uses as much as digits as its factorization.

87790561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 105840, while the sum is 43.

The square root of 87790561 is about 9369.6617334886. The cubic root of 87790561 is about 444.4428679782.

The spelling of 87790561 in words is "eighty-seven million, seven hundred ninety thousand, five hundred sixty-one".