638376091 has 2 divisors, whose sum is σ = 638376092. Its totient is φ = 638376090.

The previous prime is 638376083. The next prime is 638376097. The reversal of 638376091 is 190673836.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 638376091 - 2³ = 638376083 is a prime.

It is not a weakly prime, because it can be changed into another prime (638376097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319188045 + 319188046.

It is an arithmetic number, because the mean of its divisors is an integer number (319188046).

Almost surely, 2^638376091 is an apocalyptic number.

638376091 is a deficient number, since it is larger than the sum of its proper divisors (1).

638376091 is an equidigital number, since it uses as much as digits as its factorization.

638376091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 163296, while the sum is 43.

The square root of 638376091 is about 25266.1055764437. The cubic root of 638376091 is about 861.0443824434.

The spelling of 638376091 in words is "six hundred thirty-eight million, three hundred seventy-six thousand, ninety-one".