81796680 has 144 divisors (see below), whose sum is σ = 309308220. Its totient is φ = 18692352.

The previous prime is 81796661. The next prime is 81796699. The reversal of 81796680 is 8669718.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81796661) and next prime (81796699).

It can be written as a sum of positive squares in 2 ways, for example, as 78535044 + 3261636 = 8862^2 + 1806^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 15322 + ... + 19958.

Almost surely, 2^81796680 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 81796680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154654110).

81796680 is an abundant number, since it is smaller than the sum of its proper divisors (227511540).

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

81796680 is a wasteful number, since it uses less digits than its factorization.

81796680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4668 (or 4654 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 81796680 is about 9044.1517015141. The cubic root of 81796680 is about 434.0887782311.

The spelling of 81796680 in words is "eighty-one million, seven hundred ninety-six thousand, six hundred eighty".