5661921 has 4 divisors (see below), whose sum is σ = 7549232. Its totient is φ = 3774612.

The previous prime is 5661911. The next prime is 5661923. The reversal of 5661921 is 1291665.

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 not a de Polignac number, because 5661921 - 2¹¹ = 5659873 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5661923) 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, 943651 + ... + 943656.

It is an arithmetic number, because the mean of its divisors is an integer number (1887308).

Almost surely, 2^5661921 is an apocalyptic number.

It is an amenable number.

5661921 is a deficient number, since it is larger than the sum of its proper divisors (1887311).

5661921 is a wasteful number, since it uses less digits than its factorization.

5661921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1887310.

The product of its digits is 3240, while the sum is 30.

The square root of 5661921 is about 2379.4791446869. The cubic root of 5661921 is about 178.2329253001.

The spelling of 5661921 in words is "five million, six hundred sixty-one thousand, nine hundred twenty-one".