81645704 has 16 divisors (see below), whose sum is σ = 174955200. Its totient is φ = 34990992.

The previous prime is 81645677. The next prime is 81645761. The reversal of 81645704 is 40754618.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 728924 + ... + 729035.

It is an arithmetic number, because the mean of its divisors is an integer number (10934700).

Almost surely, 2^81645704 is an apocalyptic number.

It is an amenable number.

81645704 is an abundant number, since it is smaller than the sum of its proper divisors (93309496).

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

81645704 is a wasteful number, since it uses less digits than its factorization.

81645704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1457972 (or 1457968 counting only the distinct ones).

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

The square root of 81645704 is about 9035.8012373004. The cubic root of 81645704 is about 433.8215410182.

The spelling of 81645704 in words is "eighty-one million, six hundred forty-five thousand, seven hundred four".