81947330 has 16 divisors (see below), whose sum is σ = 152592120. Its totient is φ = 31648512.

The previous prime is 81947329. The next prime is 81947351. The reversal of 81947330 is 3374918.

It can be written as a sum of positive squares in 4 ways, for example, as 70543201 + 11404129 = 8399^2 + 3377^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 140999 + ... + 141578.

Almost surely, 2^81947330 is an apocalyptic number.

81947330 is a deficient number, since it is larger than the sum of its proper divisors (70644790).

81947330 is a wasteful number, since it uses less digits than its factorization.

81947330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282613.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 81947330 is about 9052.4764567493. The cubic root of 81947330 is about 434.3551108330.

The spelling of 81947330 in words is "eighty-one million, nine hundred forty-seven thousand, three hundred thirty".