81895507 has 16 divisors (see below), whose sum is σ = 86977440. Its totient is φ = 76995072.

The previous prime is 81895487. The next prime is 81895537. The reversal of 81895507 is 70559818.

It is a cyclic number.

It is not a de Polignac number, because 81895507 - 2⁷ = 81895379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81895537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 219373 + ... + 219745.

It is an arithmetic number, because the mean of its divisors is an integer number (5436090).

Almost surely, 2^81895507 is an apocalyptic number.

81895507 is a deficient number, since it is larger than the sum of its proper divisors (5081933).

81895507 is a wasteful number, since it uses less digits than its factorization.

81895507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 582.

The product of its (nonzero) digits is 100800, while the sum is 43.

The square root of 81895507 is about 9049.6136381616. The cubic root of 81895507 is about 434.2635303363.

The spelling of 81895507 in words is "eighty-one million, eight hundred ninety-five thousand, five hundred seven".