56237821 has 2 divisors, whose sum is σ = 56237822. Its totient is φ = 56237820.

The previous prime is 56237767. The next prime is 56237827. The reversal of 56237821 is 12873265.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55800900 + 436921 = 7470^2 + 661^2 .

It is a cyclic number.

It is not a de Polignac number, because 56237821 - 2⁷ = 56237693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56237827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28118910 + 28118911.

It is an arithmetic number, because the mean of its divisors is an integer number (28118911).

Almost surely, 2^56237821 is an apocalyptic number.

It is an amenable number.

56237821 is a deficient number, since it is larger than the sum of its proper divisors (1).

56237821 is an equidigital number, since it uses as much as digits as its factorization.

56237821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 34.

The square root of 56237821 is about 7499.1880227129. The cubic root of 56237821 is about 383.1270612154.

It can be divided in two parts, 562 and 37821, that added together give a palindrome (38383).

The spelling of 56237821 in words is "fifty-six million, two hundred thirty-seven thousand, eight hundred twenty-one".