6445881 has 24 divisors (see below), whose sum is σ = 10304840. Its totient is φ = 3856896.

The previous prime is 6445871. The next prime is 6445919. The reversal of 6445881 is 1885446.

6445881 is a `hidden beast` number, since 644 + 5 + 8 + 8 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 467856 + 5978025 = 684^2 + 2445^2 .

It is not a de Polignac number, because 6445881 - 2⁵ = 6445849 is a prime.

It is a super-2 number, since 2×6445881² = 83098763732322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (6445811) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3585 + ... + 5073.

Almost surely, 2^6445881 is an apocalyptic number.

It is an amenable number.

6445881 is a deficient number, since it is larger than the sum of its proper divisors (3858959).

6445881 is a wasteful number, since it uses less digits than its factorization.

6445881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1545 (or 1542 counting only the distinct ones).

The product of its digits is 30720, while the sum is 36.

The square root of 6445881 is about 2538.8739630001. The cubic root of 6445881 is about 186.1061655443.

Subtracting from 6445881 its sum of digits (36), we obtain a triangular number (6445845 = T₃₅₉₀).

The spelling of 6445881 in words is "six million, four hundred forty-five thousand, eight hundred eighty-one".