81788895 has 24 divisors (see below), whose sum is σ = 141987456. Its totient is φ = 43553088.

The previous prime is 81788867. The next prime is 81788923. The reversal of 81788895 is 59888718.

It is an interprime number because it is at equal distance from previous prime (81788867) and next prime (81788923).

It is not a de Polignac number, because 81788895 - 2⁶ = 81788831 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 43954 + ... + 45776.

It is an arithmetic number, because the mean of its divisors is an integer number (5916144).

Almost surely, 2^81788895 is an apocalyptic number.

81788895 is a deficient number, since it is larger than the sum of its proper divisors (60198561).

81788895 is a wasteful number, since it uses less digits than its factorization.

81788895 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2831 (or 2828 counting only the distinct ones).

The product of its digits is 1290240, while the sum is 54.

The square root of 81788895 is about 9043.7213026497. The cubic root of 81788895 is about 434.0750063260.

The spelling of 81788895 in words is "eighty-one million, seven hundred eighty-eight thousand, eight hundred ninety-five".