81724020 has 48 divisors (see below), whose sum is σ = 261518208. Its totient is φ = 18679680.

The previous prime is 81724007. The next prime is 81724021. The reversal of 81724020 is 2042718.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81724021) 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 15 ways as a sum of consecutive naturals, for example, 96871 + ... + 97710.

It is an arithmetic number, because the mean of its divisors is an integer number (5448296).

Almost surely, 2^81724020 is an apocalyptic number.

It is an amenable number.

81724020 is an abundant number, since it is smaller than the sum of its proper divisors (179794188).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81724020 is a wasteful number, since it uses less digits than its factorization.

81724020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194600 (or 194598 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 81724020 is about 9040.1338485666. The cubic root of 81724020 is about 433.9602064500.

Adding to 81724020 its reverse (2042718), we get a palindrome (83766738).

The spelling of 81724020 in words is "eighty-one million, seven hundred twenty-four thousand, twenty".