6487721 has 4 divisors (see below), whose sum is σ = 6829200. Its totient is φ = 6146244.

The previous prime is 6487687. The next prime is 6487751. The reversal of 6487721 is 1277846.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1277846 = 2 ⋅638923.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6487721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6487751) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 170711 + ... + 170748.

It is an arithmetic number, because the mean of its divisors is an integer number (1707300).

Almost surely, 2^6487721 is an apocalyptic number.

It is an amenable number.

6487721 is a deficient number, since it is larger than the sum of its proper divisors (341479).

6487721 is a wasteful number, since it uses less digits than its factorization.

6487721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341478.

The product of its digits is 18816, while the sum is 35.

The square root of 6487721 is about 2547.1005084213. The cubic root of 6487721 is about 186.5079670856.

The spelling of 6487721 in words is "six million, four hundred eighty-seven thousand, seven hundred twenty-one".