81064646 has 16 divisors (see below), whose sum is σ = 132304704. Its totient is φ = 37027584.

The previous prime is 81064601. The next prime is 81064649. The reversal of 81064646 is 64646018.

It is a super-2 number, since 2×81064646² = 13142953662210632, which contains 22 as substring.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81064649) 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, 13550 + ... + 18593.

It is an arithmetic number, because the mean of its divisors is an integer number (8269044).

Almost surely, 2^81064646 is an apocalyptic number.

81064646 is a deficient number, since it is larger than the sum of its proper divisors (51240058).

81064646 is a wasteful number, since it uses less digits than its factorization.

81064646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32255.

The product of its (nonzero) digits is 27648, while the sum is 35.

The square root of 81064646 is about 9003.5907281484. The cubic root of 81064646 is about 432.7899462440.

It can be divided in two parts, 810 and 64646, that added together give a palindrome (65456).

The spelling of 81064646 in words is "eighty-one million, sixty-four thousand, six hundred forty-six".