56221309 has 2 divisors, whose sum is σ = 56221310. Its totient is φ = 56221308.

The previous prime is 56221301. The next prime is 56221313. The reversal of 56221309 is 90312265.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33895684 + 22325625 = 5822^2 + 4725^2 .

It is a cyclic number.

It is not a de Polignac number, because 56221309 - 2³ = 56221301 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56221301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28110654 + 28110655.

It is an arithmetic number, because the mean of its divisors is an integer number (28110655).

Almost surely, 2^56221309 is an apocalyptic number.

It is an amenable number.

56221309 is a deficient number, since it is larger than the sum of its proper divisors (1).

56221309 is an equidigital number, since it uses as much as digits as its factorization.

56221309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 56221309 is about 7498.0870227012. The cubic root of 56221309 is about 383.0895608691.

The spelling of 56221309 in words is "fifty-six million, two hundred twenty-one thousand, three hundred nine".