81646822 has 4 divisors (see below), whose sum is σ = 122470236. Its totient is φ = 40823410.

The previous prime is 81646813. The next prime is 81646841. The reversal of 81646822 is 22864618.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20411704 + ... + 20411707.

It is an arithmetic number, because the mean of its divisors is an integer number (30617559).

Almost surely, 2^81646822 is an apocalyptic number.

81646822 is a deficient number, since it is larger than the sum of its proper divisors (40823414).

81646822 is a wasteful number, since it uses less digits than its factorization.

81646822 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40823413.

The product of its digits is 36864, while the sum is 37.

The square root of 81646822 is about 9035.8631021060. The cubic root of 81646822 is about 433.8235211603.

The spelling of 81646822 in words is "eighty-one million, six hundred forty-six thousand, eight hundred twenty-two".