81863930 has 8 divisors (see below), whose sum is σ = 147355092. Its totient is φ = 32745568.

The previous prime is 81863917. The next prime is 81863981. The reversal of 81863930 is 3936818.

It can be written as a sum of positive squares in 2 ways, for example, as 81126049 + 737881 = 9007^2 + 859^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4093187 + ... + 4093206.

Almost surely, 2^81863930 is an apocalyptic number.

81863930 is a deficient number, since it is larger than the sum of its proper divisors (65491162).

81863930 is a wasteful number, since it uses less digits than its factorization.

81863930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8186400.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 81863930 is about 9047.8688098358. The cubic root of 81863930 is about 434.2077091938.

The spelling of 81863930 in words is "eighty-one million, eight hundred sixty-three thousand, nine hundred thirty".