81610265 has 16 divisors (see below), whose sum is σ = 107726976. Its totient is φ = 59348080.

The previous prime is 81610261. The next prime is 81610267. The reversal of 81610265 is 56201618.

81610265 = 456² + 457² + ... + 697².

It is a happy number.

It is not a de Polignac number, because 81610265 - 2² = 81610261 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81610261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 524 + ... + 12786.

It is an arithmetic number, because the mean of its divisors is an integer number (6732936).

Almost surely, 2^81610265 is an apocalyptic number.

It is an amenable number.

81610265 is a deficient number, since it is larger than the sum of its proper divisors (26116711).

81610265 is a wasteful number, since it uses less digits than its factorization.

81610265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12301 (or 12279 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 81610265 is about 9033.8399919414. The cubic root of 81610265 is about 433.7587639795.

The spelling of 81610265 in words is "eighty-one million, six hundred ten thousand, two hundred sixty-five".