81962505 has 24 divisors (see below), whose sum is σ = 144480960. Its totient is φ = 42971040.

The previous prime is 81962479. The next prime is 81962509. The reversal of 81962505 is 50526918.

It is a happy number.

It is not a de Polignac number, because 81962505 - 2⁵ = 81962473 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81962505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81962509) 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 23 ways as a sum of consecutive naturals, for example, 12781 + ... + 18090.

It is an arithmetic number, because the mean of its divisors is an integer number (6020040).

Almost surely, 2^81962505 is an apocalyptic number.

It is an amenable number.

81962505 is a deficient number, since it is larger than the sum of its proper divisors (62518455).

81962505 is a wasteful number, since it uses less digits than its factorization.

81962505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30941 (or 30938 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 81962505 is about 9053.3145863822. The cubic root of 81962505 is about 434.3819204598.

It can be divided in two parts, 8196 and 2505, that added together give a palindrome (10701).

The spelling of 81962505 in words is "eighty-one million, nine hundred sixty-two thousand, five hundred five".