6571371661 has 4 divisors (see below), whose sum is σ = 6783351424. Its totient is φ = 6359391900.

The previous prime is 6571371649. The next prime is 6571371683. The reversal of 6571371661 is 1661731756.

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.

It is a cyclic number.

It is not a de Polignac number, because 6571371661 - 2⁵ = 6571371629 is a prime.

It is a super-3 number, since 3×6571371661³ (a number of 30 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6571371161) 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, 105989835 + ... + 105989896.

It is an arithmetic number, because the mean of its divisors is an integer number (1695837856).

Almost surely, 2^6571371661 is an apocalyptic number.

It is an amenable number.

6571371661 is a deficient number, since it is larger than the sum of its proper divisors (211979763).

6571371661 is a wasteful number, since it uses less digits than its factorization.

6571371661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211979762.

The product of its digits is 158760, while the sum is 43.

The square root of 6571371661 is about 81063.9973169347. The cubic root of 6571371661 is about 1873.0613834162.

The spelling of 6571371661 in words is "six billion, five hundred seventy-one million, three hundred seventy-one thousand, six hundred sixty-one".