81510887 has 2 divisors, whose sum is σ = 81510888. Its totient is φ = 81510886.

The previous prime is 81510883. The next prime is 81510899. The reversal of 81510887 is 78801518.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81510887 - 2² = 81510883 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81510887.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81510881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40755443 + 40755444.

It is an arithmetic number, because the mean of its divisors is an integer number (40755444).

Almost surely, 2^81510887 is an apocalyptic number.

81510887 is a deficient number, since it is larger than the sum of its proper divisors (1).

81510887 is an equidigital number, since it uses as much as digits as its factorization.

81510887 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17920, while the sum is 38.

The square root of 81510887 is about 9028.3379976605. The cubic root of 81510887 is about 433.5826276922.

The spelling of 81510887 in words is "eighty-one million, five hundred ten thousand, eight hundred eighty-seven".