8721537 has 8 divisors (see below), whose sum is σ = 12685920. Its totient is φ = 5285760.

The previous prime is 8721533. The next prime is 8721539. The reversal of 8721537 is 7351278.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 8721537 - 2² = 8721533 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 264289 = 8721537 / (8 + 7 + 2 + 1 + 5 + 3 + 7).

8721537 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 8721498 and 8721507.

It is not an unprimeable number, because it can be changed into a prime (8721533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 132112 + ... + 132177.

It is an arithmetic number, because the mean of its divisors is an integer number (1585740).

Almost surely, 2^8721537 is an apocalyptic number.

It is an amenable number.

8721537 is a deficient number, since it is larger than the sum of its proper divisors (3964383).

8721537 is a wasteful number, since it uses less digits than its factorization.

8721537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 264303.

The product of its digits is 11760, while the sum is 33.

The square root of 8721537 is about 2953.2248475184. The cubic root of 8721537 is about 205.8405858146.

The spelling of 8721537 in words is "eight million, seven hundred twenty-one thousand, five hundred thirty-seven".