81663782 has 8 divisors (see below), whose sum is σ = 123390216. Its totient is φ = 40533712.

The previous prime is 81663779. The next prime is 81663787. The reversal of 81663782 is 28736618.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81663787) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 148748 + ... + 149295.

It is an arithmetic number, because the mean of its divisors is an integer number (15423777).

Almost surely, 2^81663782 is an apocalyptic number.

81663782 is a deficient number, since it is larger than the sum of its proper divisors (41726434).

81663782 is a wasteful number, since it uses less digits than its factorization.

81663782 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 298182.

The product of its digits is 96768, while the sum is 41.

The square root of 81663782 is about 9036.8015359418. The cubic root of 81663782 is about 433.8535575918.

The spelling of 81663782 in words is "eighty-one million, six hundred sixty-three thousand, seven hundred eighty-two".