81866830 has 16 divisors (see below), whose sum is σ = 148422960. Its totient is φ = 32510592.

The previous prime is 81866789. The next prime is 81866857. The reversal of 81866830 is 3866818.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 28059 + ... + 30838.

It is an arithmetic number, because the mean of its divisors is an integer number (9276435).

Almost surely, 2^81866830 is an apocalyptic number.

81866830 is a deficient number, since it is larger than the sum of its proper divisors (66556130).

81866830 is a wasteful number, since it uses less digits than its factorization.

81866830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59043.

The product of its (nonzero) digits is 55296, while the sum is 40.

The square root of 81866830 is about 9048.0290671505. The cubic root of 81866830 is about 434.2128363501.

The spelling of 81866830 in words is "eighty-one million, eight hundred sixty-six thousand, eight hundred thirty".