6521971 has 4 divisors (see below), whose sum is σ = 6583032. Its totient is φ = 6460912.

The previous prime is 6521951. The next prime is 6521987. The reversal of 6521971 is 1791256.

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

It is a cyclic number.

It is not a de Polignac number, because 6521971 - 2⁷ = 6521843 is a prime.

It is a super-2 number, since 2×6521971² = 85072211449682, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6521951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30370 + ... + 30583.

It is an arithmetic number, because the mean of its divisors is an integer number (1645758).

Almost surely, 2^6521971 is an apocalyptic number.

6521971 is a deficient number, since it is larger than the sum of its proper divisors (61061).

6521971 is a wasteful number, since it uses less digits than its factorization.

6521971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61060.

The product of its digits is 3780, while the sum is 31.

The square root of 6521971 is about 2553.8149893835. The cubic root of 6521971 is about 186.8355957306.

The spelling of 6521971 in words is "six million, five hundred twenty-one thousand, nine hundred seventy-one".