640189499 has 2 divisors, whose sum is σ = 640189500. Its totient is φ = 640189498.

The previous prime is 640189493. The next prime is 640189531. The reversal of 640189499 is 994981046.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 640189499 - 2⁴ = 640189483 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (640189493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320094749 + 320094750.

It is an arithmetic number, because the mean of its divisors is an integer number (320094750).

Almost surely, 2^640189499 is an apocalyptic number.

640189499 is a deficient number, since it is larger than the sum of its proper divisors (1).

640189499 is an equidigital number, since it uses as much as digits as its factorization.

640189499 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 559872, while the sum is 50.

The square root of 640189499 is about 25301.9663069889. The cubic root of 640189499 is about 861.8589224568.

The spelling of 640189499 in words is "six hundred forty million, one hundred eighty-nine thousand, four hundred ninety-nine".