81645074 has 24 divisors (see below), whose sum is σ = 143219340. Its totient is φ = 34804896.

The previous prime is 81645073. The next prime is 81645077. The reversal of 81645074 is 47054618.

It can be written as a sum of positive squares in 2 ways, for example, as 49098049 + 32547025 = 7007^2 + 5705^2 .

It is not an unprimeable number, because it can be changed into a prime (81645073) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17192 + ... + 21420.

Almost surely, 2^81645074 is an apocalyptic number.

81645074 is a deficient number, since it is larger than the sum of its proper divisors (61574266).

81645074 is a wasteful number, since it uses less digits than its factorization.

81645074 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4442 (or 4435 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 35.

The square root of 81645074 is about 9035.7663759086. The cubic root of 81645074 is about 433.8204251879.

The spelling of 81645074 in words is "eighty-one million, six hundred forty-five thousand, seventy-four".