87291661 has 2 divisors, whose sum is σ = 87291662. Its totient is φ = 87291660.

The previous prime is 87291641. The next prime is 87291697. The reversal of 87291661 is 16619278.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49702500 + 37589161 = 7050^2 + 6131^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87291661 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87291641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43645830 + 43645831.

It is an arithmetic number, because the mean of its divisors is an integer number (43645831).

Almost surely, 2^87291661 is an apocalyptic number.

It is an amenable number.

87291661 is a deficient number, since it is larger than the sum of its proper divisors (1).

87291661 is an equidigital number, since it uses as much as digits as its factorization.

87291661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 40.

The square root of 87291661 is about 9343.0006421920. Note that the first 3 decimals coincide. The cubic root of 87291661 is about 443.5993684068.

The spelling of 87291661 in words is "eighty-seven million, two hundred ninety-one thousand, six hundred sixty-one".