81564466 has 8 divisors (see below), whose sum is σ = 122436720. Its totient is φ = 40752228.

The previous prime is 81564451. The next prime is 81564467. The reversal of 81564466 is 66446518.

It is a happy number.

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

It is a super-2 number, since 2×81564466² = 13305524227730312, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81564467) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 11436 + ... + 17143.

It is an arithmetic number, because the mean of its divisors is an integer number (15304590).

Almost surely, 2^81564466 is an apocalyptic number.

81564466 is a deficient number, since it is larger than the sum of its proper divisors (40872254).

81564466 is a wasteful number, since it uses less digits than its factorization.

81564466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30008.

The product of its digits is 138240, while the sum is 40.

The square root of 81564466 is about 9031.3047783806. The cubic root of 81564466 is about 433.6776081962.

The spelling of 81564466 in words is "eighty-one million, five hundred sixty-four thousand, four hundred sixty-six".