81669926 has 48 divisors (see below), whose sum is σ = 139454784. Its totient is φ = 35822592.

The previous prime is 81669899. The next prime is 81669937. The reversal of 81669926 is 62996618.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 841910 + ... + 842006.

It is an arithmetic number, because the mean of its divisors is an integer number (2905308).

Almost surely, 2^81669926 is an apocalyptic number.

81669926 is a deficient number, since it is larger than the sum of its proper divisors (57784858).

81669926 is a wasteful number, since it uses less digits than its factorization.

81669926 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225 (or 212 counting only the distinct ones).

The product of its digits is 279936, while the sum is 47.

The square root of 81669926 is about 9037.1414728331. The cubic root of 81669926 is about 433.8644376879.

The spelling of 81669926 in words is "eighty-one million, six hundred sixty-nine thousand, nine hundred twenty-six".