637228421 has 2 divisors, whose sum is σ = 637228422. Its totient is φ = 637228420.

The previous prime is 637228369. The next prime is 637228439. The reversal of 637228421 is 124822736.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 495285025 + 141943396 = 22255^2 + 11914^2 .

It is a cyclic number.

It is not a de Polignac number, because 637228421 - 2¹⁸ = 636966277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (637228321) 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, 318614210 + 318614211.

It is an arithmetic number, because the mean of its divisors is an integer number (318614211).

Almost surely, 2^637228421 is an apocalyptic number.

It is an amenable number.

637228421 is a deficient number, since it is larger than the sum of its proper divisors (1).

637228421 is an equidigital number, since it uses as much as digits as its factorization.

637228421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 35.

The square root of 637228421 is about 25243.3837074193. The cubic root of 637228421 is about 860.5280788603.

The spelling of 637228421 in words is "six hundred thirty-seven million, two hundred twenty-eight thousand, four hundred twenty-one".