6521993 has 4 divisors (see below), whose sum is σ = 6681108. Its totient is φ = 6362880.

The previous prime is 6521987. The next prime is 6522001. The reversal of 6521993 is 3991256.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2866249 + 3655744 = 1693^2 + 1912^2 .

It is a cyclic number.

It is not a de Polignac number, because 6521993 - 2⁶ = 6521929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6521923) 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, 79496 + ... + 79577.

It is an arithmetic number, because the mean of its divisors is an integer number (1670277).

Almost surely, 2^6521993 is an apocalyptic number.

It is an amenable number.

6521993 is a deficient number, since it is larger than the sum of its proper divisors (159115).

6521993 is a wasteful number, since it uses less digits than its factorization.

6521993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159114.

The product of its digits is 14580, while the sum is 35.

The square root of 6521993 is about 2553.8192966614. The cubic root of 6521993 is about 186.8358058091.

The spelling of 6521993 in words is "six million, five hundred twenty-one thousand, nine hundred ninety-three".