81776444 has 6 divisors (see below), whose sum is σ = 143108784. Its totient is φ = 40888220.

The previous prime is 81776441. The next prime is 81776447. The reversal of 81776444 is 44467718.

It is an interprime number because it is at equal distance from previous prime (81776441) and next prime (81776447).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81776441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10222052 + ... + 10222059.

It is an arithmetic number, because the mean of its divisors is an integer number (23851464).

Almost surely, 2^81776444 is an apocalyptic number.

It is an amenable number.

81776444 is a deficient number, since it is larger than the sum of its proper divisors (61332340).

81776444 is a wasteful number, since it uses less digits than its factorization.

81776444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20444115 (or 20444113 counting only the distinct ones).

The product of its digits is 150528, while the sum is 41.

The square root of 81776444 is about 9043.0328983146. The cubic root of 81776444 is about 434.0529783062.

The spelling of 81776444 in words is "eighty-one million, seven hundred seventy-six thousand, four hundred forty-four".