81764964 has 60 divisors (see below), whose sum is σ = 216740524. Its totient is φ = 26873856.

The previous prime is 81764941. The next prime is 81764981. The reversal of 81764964 is 46946718.

It can be written as a sum of positive squares in 2 ways, for example, as 17892900 + 63872064 = 4230^2 + 7992^2 .

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 21924 + ... + 25380.

Almost surely, 2^81764964 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81764964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108370262).

81764964 is an abundant number, since it is smaller than the sum of its proper divisors (134975560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81764964 is a wasteful number, since it uses less digits than its factorization.

81764964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3546 (or 3535 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 81764964 is about 9042.3981332388. The cubic root of 81764964 is about 434.0326661758.

It can be divided in two parts, 81764 and 964, that added together give a palindrome (82728).

The spelling of 81764964 in words is "eighty-one million, seven hundred sixty-four thousand, nine hundred sixty-four".