81635265 has 12 divisors (see below), whose sum is σ = 141501204. Its totient is φ = 43538784.

The previous prime is 81635233. The next prime is 81635293. The reversal of 81635265 is 56253618.

It can be written as a sum of positive squares in 2 ways, for example, as 62869041 + 18766224 = 7929^2 + 4332^2 .

It is not a de Polignac number, because 81635265 - 2⁵ = 81635233 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 907014 + ... + 907103.

It is an arithmetic number, because the mean of its divisors is an integer number (11791767).

Almost surely, 2^81635265 is an apocalyptic number.

It is an amenable number.

81635265 is a deficient number, since it is larger than the sum of its proper divisors (59865939).

81635265 is a wasteful number, since it uses less digits than its factorization.

81635265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1814128 (or 1814125 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 81635265 is about 9035.2235722200. The cubic root of 81635265 is about 433.8030511453.

The spelling of 81635265 in words is "eighty-one million, six hundred thirty-five thousand, two hundred sixty-five".