81964663 has 32 divisors (see below), whose sum is σ = 97708032. Its totient is φ = 68006400.

The previous prime is 81964607. The next prime is 81964669. The reversal of 81964663 is 36646918.

It is not a de Polignac number, because 81964663 - 2⁹ = 81964151 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81964669) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 725295 + ... + 725407.

It is an arithmetic number, because the mean of its divisors is an integer number (3053376).

Almost surely, 2^81964663 is an apocalyptic number.

81964663 is a deficient number, since it is larger than the sum of its proper divisors (15743369).

81964663 is a wasteful number, since it uses less digits than its factorization.

81964663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255.

The product of its digits is 186624, while the sum is 43.

The square root of 81964663 is about 9053.4337684660. The cubic root of 81964663 is about 434.3857327231.

The spelling of 81964663 in words is "eighty-one million, nine hundred sixty-four thousand, six hundred sixty-three".