81224691 has 16 divisors (see below), whose sum is σ = 116246304. Its totient is φ = 50264064.

The previous prime is 81224683. The next prime is 81224701. The reversal of 81224691 is 19642218.

It is not a de Polignac number, because 81224691 - 2³ = 81224683 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81224641) 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 15 ways as a sum of consecutive naturals, for example, 7186 + ... + 14631.

It is an arithmetic number, because the mean of its divisors is an integer number (7265394).

Almost surely, 2^81224691 is an apocalyptic number.

81224691 is a deficient number, since it is larger than the sum of its proper divisors (35021613).

81224691 is a wasteful number, since it uses less digits than its factorization.

81224691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21910.

The product of its digits is 6912, while the sum is 33.

The square root of 81224691 is about 9012.4741885899. The cubic root of 81224691 is about 433.0745764196.

The spelling of 81224691 in words is "eighty-one million, two hundred twenty-four thousand, six hundred ninety-one".