81861350 has 24 divisors (see below), whose sum is σ = 152672520. Its totient is φ = 32656320.

The previous prime is 81861349. The next prime is 81861389. The reversal of 81861350 is 5316818.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 18449 + ... + 22451.

It is an arithmetic number, because the mean of its divisors is an integer number (6361355).

Almost surely, 2^81861350 is an apocalyptic number.

81861350 is a deficient number, since it is larger than the sum of its proper divisors (70811170).

81861350 is a wasteful number, since it uses less digits than its factorization.

81861350 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4424 (or 4419 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 81861350 is about 9047.7262337009. The cubic root of 81861350 is about 434.2031476909.

The spelling of 81861350 in words is "eighty-one million, eight hundred sixty-one thousand, three hundred fifty".