438388021 has 2 divisors, whose sum is σ = 438388022. Its totient is φ = 438388020.

The previous prime is 438388003. The next prime is 438388033. The reversal of 438388021 is 120883834.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 303247396 + 135140625 = 17414^2 + 11625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-438388021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (438388001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 219194010 + 219194011.

It is an arithmetic number, because the mean of its divisors is an integer number (219194011).

Almost surely, 2^438388021 is an apocalyptic number.

It is an amenable number.

438388021 is a deficient number, since it is larger than the sum of its proper divisors (1).

438388021 is an equidigital number, since it uses as much as digits as its factorization.

438388021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36864, while the sum is 37.

The square root of 438388021 is about 20937.7176645402. The cubic root of 438388021 is about 759.6605253260.

The spelling of 438388021 in words is "four hundred thirty-eight million, three hundred eighty-eight thousand, twenty-one".