81447790 has 16 divisors (see below), whose sum is σ = 147083040. Its totient is φ = 32473120.

The previous prime is 81447763. The next prime is 81447797. The reversal of 81447790 is 9774418.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81447797) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9985 + ... + 16204.

It is an arithmetic number, because the mean of its divisors is an integer number (9192690).

Almost surely, 2^81447790 is an apocalyptic number.

81447790 is a deficient number, since it is larger than the sum of its proper divisors (65635250).

81447790 is a wasteful number, since it uses less digits than its factorization.

81447790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26507.

The product of its (nonzero) digits is 56448, while the sum is 40.

The square root of 81447790 is about 9024.8429349214. The cubic root of 81447790 is about 433.4707210653.

The spelling of 81447790 in words is "eighty-one million, four hundred forty-seven thousand, seven hundred ninety".