6491987 has 4 divisors (see below), whose sum is σ = 6555120. Its totient is φ = 6428856.

The previous prime is 6491971. The next prime is 6491993. The reversal of 6491987 is 7891946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7891946 = 2 ⋅3945973.

It is a cyclic number.

It is not a de Polignac number, because 6491987 - 2⁴ = 6491971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6494987) 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, 31412 + ... + 31617.

It is an arithmetic number, because the mean of its divisors is an integer number (1638780).

Almost surely, 2^6491987 is an apocalyptic number.

6491987 is a deficient number, since it is larger than the sum of its proper divisors (63133).

6491987 is a wasteful number, since it uses less digits than its factorization.

6491987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63132.

The product of its digits is 108864, while the sum is 44.

The square root of 6491987 is about 2547.9377935892. The cubic root of 6491987 is about 186.5488375576.

The spelling of 6491987 in words is "six million, four hundred ninety-one thousand, nine hundred eighty-seven".