81666074 has 16 divisors (see below), whose sum is σ = 140289408. Its totient is φ = 34927152.

The previous prime is 81666071. The next prime is 81666131. The reversal of 81666074 is 47066618.

It is not an unprimeable number, because it can be changed into a prime (81666071) 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 7 ways as a sum of consecutive naturals, for example, 1244 + ... + 12840.

It is an arithmetic number, because the mean of its divisors is an integer number (8768088).

Almost surely, 2^81666074 is an apocalyptic number.

81666074 is a deficient number, since it is larger than the sum of its proper divisors (58623334).

81666074 is a wasteful number, since it uses less digits than its factorization.

81666074 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12109.

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 81666074 is about 9036.9283498321. The cubic root of 81666074 is about 433.8576164415.

The spelling of 81666074 in words is "eighty-one million, six hundred sixty-six thousand, seventy-four".