438535681 has 2 divisors, whose sum is σ = 438535682. Its totient is φ = 438535680.

The previous prime is 438535679. The next prime is 438535693. The reversal of 438535681 is 186535834.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 261113281 + 177422400 = 16159^2 + 13320^2 .

It is a cyclic number.

It is not a de Polignac number, because 438535681 - 2¹ = 438535679 is a prime.

It is a super-2 number, since 2×438535681² = 384627087020267522, which contains 22 as substring.

Together with 438535679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (438535661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 219267840 + 219267841.

It is an arithmetic number, because the mean of its divisors is an integer number (219267841).

Almost surely, 2^438535681 is an apocalyptic number.

It is an amenable number.

438535681 is a deficient number, since it is larger than the sum of its proper divisors (1).

438535681 is an equidigital number, since it uses as much as digits as its factorization.

438535681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 345600, while the sum is 43.

The square root of 438535681 is about 20941.2435399620. The cubic root of 438535681 is about 759.7458066112.

The spelling of 438535681 in words is "four hundred thirty-eight million, five hundred thirty-five thousand, six hundred eighty-one".