81645080 has 32 divisors (see below), whose sum is σ = 200402640. Its totient is φ = 29688960.

The previous prime is 81645079. The next prime is 81645097. The reversal of 81645080 is 8054618.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92339 + ... + 93218.

Almost surely, 2^81645080 is an apocalyptic number.

It is an amenable number.

81645080 is an abundant number, since it is smaller than the sum of its proper divisors (118757560).

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

81645080 is a wasteful number, since it uses less digits than its factorization.

81645080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185579 (or 185575 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 81645080 is about 9035.7667079225. The cubic root of 81645080 is about 433.8204358148.

Adding to 81645080 its reverse (8054618), we get a palindrome (89699698).

The spelling of 81645080 in words is "eighty-one million, six hundred forty-five thousand, eighty".