87549991 has 2 divisors, whose sum is σ = 87549992. Its totient is φ = 87549990.

The previous prime is 87549971. The next prime is 87549997. The reversal of 87549991 is 19994578.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87549991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (87549997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43774995 + 43774996.

It is an arithmetic number, because the mean of its divisors is an integer number (43774996).

Almost surely, 2^87549991 is an apocalyptic number.

87549991 is a deficient number, since it is larger than the sum of its proper divisors (1).

87549991 is an equidigital number, since it uses as much as digits as its factorization.

87549991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 816480, while the sum is 52.

The square root of 87549991 is about 9356.8152167284. The cubic root of 87549991 is about 444.0365318398.

The spelling of 87549991 in words is "eighty-seven million, five hundred forty-nine thousand, nine hundred ninety-one".