81975466 has 4 divisors (see below), whose sum is σ = 122963202. Its totient is φ = 40987732.

The previous prime is 81975451. The next prime is 81975499. The reversal of 81975466 is 66457918.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 59213025 + 22762441 = 7695^2 + 4771^2 .

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 as a sum of consecutive naturals, namely, 20493865 + ... + 20493868.

Almost surely, 2^81975466 is an apocalyptic number.

81975466 is a deficient number, since it is larger than the sum of its proper divisors (40987736).

81975466 is a wasteful number, since it uses less digits than its factorization.

81975466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40987735.

The product of its digits is 362880, while the sum is 46.

The square root of 81975466 is about 9054.0303732647. The cubic root of 81975466 is about 434.4048159993.

The spelling of 81975466 in words is "eighty-one million, nine hundred seventy-five thousand, four hundred sixty-six".