81781826 has 8 divisors (see below), whose sum is σ = 140197440. Its totient is φ = 35049348.

The previous prime is 81781823. The next prime is 81781841. The reversal of 81781826 is 62818718.

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

It is not an unprimeable number, because it can be changed into a prime (81781823) 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, 2920766 + ... + 2920793.

It is an arithmetic number, because the mean of its divisors is an integer number (17524680).

Almost surely, 2^81781826 is an apocalyptic number.

81781826 is a deficient number, since it is larger than the sum of its proper divisors (58415614).

81781826 is a wasteful number, since it uses less digits than its factorization.

81781826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5841568.

The product of its digits is 43008, while the sum is 41.

The square root of 81781826 is about 9043.3304705733. The cubic root of 81781826 is about 434.0625002898.

The spelling of 81781826 in words is "eighty-one million, seven hundred eighty-one thousand, eight hundred twenty-six".