56405221 has 4 divisors (see below), whose sum is σ = 56421792. Its totient is φ = 56388652.

The previous prime is 56405191. The next prime is 56405231. The reversal of 56405221 is 12250465.

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 56405221 - 2⁵ = 56405189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (56405231) 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, 1105 + ... + 10678.

It is an arithmetic number, because the mean of its divisors is an integer number (14105448).

Almost surely, 2^56405221 is an apocalyptic number.

It is an amenable number.

56405221 is a deficient number, since it is larger than the sum of its proper divisors (16571).

56405221 is a wasteful number, since it uses less digits than its factorization.

56405221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16570.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 56405221 is about 7510.3409376672. The cubic root of 56405221 is about 383.5068290049.

Adding to 56405221 its reverse (12250465), we get a palindrome (68655686).

The spelling of 56405221 in words is "fifty-six million, four hundred five thousand, two hundred twenty-one".