81724601 has 12 divisors (see below), whose sum is σ = 97638948. Its totient is φ = 68154912.

The previous prime is 81724597. The next prime is 81724607. The reversal of 81724601 is 10642718.

It can be written as a sum of positive squares in 2 ways, for example, as 61465600 + 20259001 = 7840^2 + 4501^2 .

It is not a de Polignac number, because 81724601 - 2² = 81724597 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81724607) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20726 + ... + 24351.

It is an arithmetic number, because the mean of its divisors is an integer number (8136579).

Almost surely, 2^81724601 is an apocalyptic number.

It is an amenable number.

81724601 is a deficient number, since it is larger than the sum of its proper divisors (15914347).

81724601 is a wasteful number, since it uses less digits than its factorization.

81724601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45128 (or 45121 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 81724601 is about 9040.1659829895. The cubic root of 81724601 is about 433.9612348310.

The spelling of 81724601 in words is "eighty-one million, seven hundred twenty-four thousand, six hundred one".