81724455 has 12 divisors (see below), whose sum is σ = 141655800. Its totient is φ = 43586352.

The previous prime is 81724429. The next prime is 81724459. The reversal of 81724455 is 55442718.

It is not a de Polignac number, because 81724455 - 2⁷ = 81724327 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81724459) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 908005 + ... + 908094.

It is an arithmetic number, because the mean of its divisors is an integer number (11804650).

Almost surely, 2^81724455 is an apocalyptic number.

81724455 is a deficient number, since it is larger than the sum of its proper divisors (59931345).

81724455 is a wasteful number, since it uses less digits than its factorization.

81724455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1816110 (or 1816107 counting only the distinct ones).

The product of its digits is 44800, while the sum is 36.

The square root of 81724455 is about 9040.1579079129. The cubic root of 81724455 is about 433.9609764087.

The spelling of 81724455 in words is "eighty-one million, seven hundred twenty-four thousand, four hundred fifty-five".