638880289 has 2 divisors, whose sum is σ = 638880290. Its totient is φ = 638880288.

The previous prime is 638880239. The next prime is 638880317. The reversal of 638880289 is 982088836.

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., 503553600 + 135326689 = 22440^2 + 11633^2 .

It is a cyclic number.

It is not a de Polignac number, because 638880289 - 2¹³ = 638872097 is a prime.

It is a super-3 number, since 3×638880289³ (a number of 27 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (638880239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319440144 + 319440145.

It is an arithmetic number, because the mean of its divisors is an integer number (319440145).

Almost surely, 2^638880289 is an apocalyptic number.

It is an amenable number.

638880289 is a deficient number, since it is larger than the sum of its proper divisors (1).

638880289 is an equidigital number, since it uses as much as digits as its factorization.

638880289 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1327104, while the sum is 52.

The square root of 638880289 is about 25276.0813616352. The cubic root of 638880289 is about 861.2710109236.

The spelling of 638880289 in words is "six hundred thirty-eight million, eight hundred eighty thousand, two hundred eighty-nine".