5661945 has 12 divisors (see below), whose sum is σ = 9814116. Its totient is φ = 3019680.

The previous prime is 5661941. The next prime is 5661961. The reversal of 5661945 is 5491665.

5661945 is a `hidden beast` number, since 566 + 1 + 94 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1929321 + 3732624 = 1389^2 + 1932^2 .

It is not a de Polignac number, because 5661945 - 2² = 5661941 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (5661941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 62866 + ... + 62955.

It is an arithmetic number, because the mean of its divisors is an integer number (817843).

Almost surely, 2^5661945 is an apocalyptic number.

It is an amenable number.

5661945 is a deficient number, since it is larger than the sum of its proper divisors (4152171).

5661945 is a wasteful number, since it uses less digits than its factorization.

5661945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125832 (or 125829 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 5661945 is about 2379.4841878021. The cubic root of 5661945 is about 178.2331771336.

It can be divided in two parts, 56 and 61945, that added together give a square (62001 = 249²).

The spelling of 5661945 in words is "five million, six hundred sixty-one thousand, nine hundred forty-five".