81663307 has 4 divisors (see below), whose sum is σ = 89087256. Its totient is φ = 74239360.

The previous prime is 81663287. The next prime is 81663319. The reversal of 81663307 is 70336618.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81663307 - 2¹⁵ = 81630539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81663397) 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, 3711958 + ... + 3711979.

It is an arithmetic number, because the mean of its divisors is an integer number (22271814).

Almost surely, 2^81663307 is an apocalyptic number.

81663307 is a deficient number, since it is larger than the sum of its proper divisors (7423949).

81663307 is a wasteful number, since it uses less digits than its factorization.

81663307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7423948.

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 81663307 is about 9036.7752544810. The cubic root of 81663307 is about 433.8527164158.

The spelling of 81663307 in words is "eighty-one million, six hundred sixty-three thousand, three hundred seven".