81435724 has 6 divisors (see below), whose sum is σ = 142512524. Its totient is φ = 40717860.

The previous prime is 81435721. The next prime is 81435737. The reversal of 81435724 is 42753418.

It is a self number, because there is not a number n which added to its sum of digits gives 81435724.

It is not an unprimeable number, because it can be changed into a prime (81435721) 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 as a sum of consecutive naturals, namely, 10179462 + ... + 10179469.

Almost surely, 2^81435724 is an apocalyptic number.

It is an amenable number.

81435724 is a deficient number, since it is larger than the sum of its proper divisors (61076800).

81435724 is a wasteful number, since it uses less digits than its factorization.

81435724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20358935 (or 20358933 counting only the distinct ones).

The product of its digits is 26880, while the sum is 34.

The square root of 81435724 is about 9024.1744220732. The cubic root of 81435724 is about 433.4493146485.

The spelling of 81435724 in words is "eighty-one million, four hundred thirty-five thousand, seven hundred twenty-four".