5571981 has 12 divisors (see below), whose sum is σ = 8079708. Its totient is φ = 3700224.

The previous prime is 5571977. The next prime is 5571989. The reversal of 5571981 is 1891755.

5571981 is a `hidden beast` number, since 5 + 571 + 9 + 81 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2223081 + 3348900 = 1491^2 + 1830^2 .

It is not a de Polignac number, because 5571981 - 2² = 5571977 is a prime.

It is a super-2 number, since 2×5571981² = 62093944528722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5571989) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1581 + ... + 3693.

It is an arithmetic number, because the mean of its divisors is an integer number (673309).

Almost surely, 2^5571981 is an apocalyptic number.

It is an amenable number.

5571981 is a deficient number, since it is larger than the sum of its proper divisors (2507727).

5571981 is a wasteful number, since it uses less digits than its factorization.

5571981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2412 (or 2409 counting only the distinct ones).

The product of its digits is 12600, while the sum is 36.

The square root of 5571981 is about 2360.5043952512. The cubic root of 5571981 is about 177.2841361852.

The spelling of 5571981 in words is "five million, five hundred seventy-one thousand, nine hundred eighty-one".