81645838 has 8 divisors (see below), whose sum is σ = 123153480. Its totient is φ = 40594680.

The previous prime is 81645833. The next prime is 81645853. The reversal of 81645838 is 83854618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 81645794 and 81645803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81645833) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 113673 + ... + 114388.

It is an arithmetic number, because the mean of its divisors is an integer number (15394185).

Almost surely, 2^81645838 is an apocalyptic number.

81645838 is a deficient number, since it is larger than the sum of its proper divisors (41507642).

81645838 is a wasteful number, since it uses less digits than its factorization.

81645838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228242.

The product of its digits is 184320, while the sum is 43.

The square root of 81645838 is about 9035.8086522458. The cubic root of 81645838 is about 433.8217783529.

The spelling of 81645838 in words is "eighty-one million, six hundred forty-five thousand, eight hundred thirty-eight".