638796901 has 2 divisors, whose sum is σ = 638796902. Its totient is φ = 638796900.

The previous prime is 638796889. The next prime is 638796911. The reversal of 638796901 is 109697836.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 626300676 + 12496225 = 25026^2 + 3535^2 .

It is a cyclic number.

It is not a de Polignac number, because 638796901 - 2¹¹ = 638794853 is a prime.

It is a super-2 number, since 2×638796901² = 816122961454407602, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638796911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319398450 + 319398451.

It is an arithmetic number, because the mean of its divisors is an integer number (319398451).

Almost surely, 2^638796901 is an apocalyptic number.

It is an amenable number.

638796901 is a deficient number, since it is larger than the sum of its proper divisors (1).

638796901 is an equidigital number, since it uses as much as digits as its factorization.

638796901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 489888, while the sum is 49.

The square root of 638796901 is about 25274.4317641367. The cubic root of 638796901 is about 861.2335376582.

The spelling of 638796901 in words is "six hundred thirty-eight million, seven hundred ninety-six thousand, nine hundred one".