81564983 has 8 divisors (see below), whose sum is σ = 84049008. Its totient is φ = 79095744.

The previous prime is 81564943. The next prime is 81565007. The reversal of 81564983 is 38946518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81564983 - 2⁶ = 81564919 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81564943) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8060 + ... + 15102.

It is an arithmetic number, because the mean of its divisors is an integer number (10506126).

Almost surely, 2^81564983 is an apocalyptic number.

81564983 is a deficient number, since it is larger than the sum of its proper divisors (2484025).

81564983 is a wasteful number, since it uses less digits than its factorization.

81564983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7393.

The product of its digits is 207360, while the sum is 44.

The square root of 81564983 is about 9031.3334009990. Note that the first 3 decimals coincide. The cubic root of 81564983 is about 433.6785244892.

The spelling of 81564983 in words is "eighty-one million, five hundred sixty-four thousand, nine hundred eighty-three".