81638350 has 12 divisors (see below), whose sum is σ = 151847424. Its totient is φ = 32655320.

The previous prime is 81638341. The next prime is 81638353. The reversal of 81638350 is 5383618.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81638353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 816334 + ... + 816433.

It is an arithmetic number, because the mean of its divisors is an integer number (12653952).

Almost surely, 2^81638350 is an apocalyptic number.

81638350 is a deficient number, since it is larger than the sum of its proper divisors (70209074).

81638350 is a wasteful number, since it uses less digits than its factorization.

81638350 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1632779 (or 1632774 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 81638350 is about 9035.3942913411. The cubic root of 81638350 is about 433.8085155548.

The spelling of 81638350 in words is "eighty-one million, six hundred thirty-eight thousand, three hundred fifty".