81832778 has 4 divisors (see below), whose sum is σ = 122749170. Its totient is φ = 40916388.

The previous prime is 81832757. The next prime is 81832783. The reversal of 81832778 is 87723818.

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

It can be written as a sum of positive squares in only one way, i.e., 80694289 + 1138489 = 8983^2 + 1067^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20458193 + ... + 20458196.

Almost surely, 2^81832778 is an apocalyptic number.

81832778 is a deficient number, since it is larger than the sum of its proper divisors (40916392).

81832778 is a wasteful number, since it uses less digits than its factorization.

81832778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40916391.

The product of its digits is 150528, while the sum is 44.

The square root of 81832778 is about 9046.1471356595. The cubic root of 81832778 is about 434.1526252894.

The spelling of 81832778 in words is "eighty-one million, eight hundred thirty-two thousand, seven hundred seventy-eight".