81965310 has 128 divisors (see below), whose sum is σ = 238740480. Its totient is φ = 17611776.

The previous prime is 81965309. The next prime is 81965327. The reversal of 81965310 is 1356918.

It is a super-2 number, since 2×81965310² = 13436624086792200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 261714 + ... + 262026.

It is an arithmetic number, because the mean of its divisors is an integer number (1865160).

Almost surely, 2^81965310 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81965310, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119370240).

81965310 is an abundant number, since it is smaller than the sum of its proper divisors (156775170).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81965310 is a wasteful number, since it uses less digits than its factorization.

81965310 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402.

The product of its (nonzero) digits is 6480, while the sum is 33.

The square root of 81965310 is about 9053.4695006942. The cubic root of 81965310 is about 434.3868756824.

The spelling of 81965310 in words is "eighty-one million, nine hundred sixty-five thousand, three hundred ten".