640481287 has 2 divisors, whose sum is σ = 640481288. Its totient is φ = 640481286.

The previous prime is 640481251. The next prime is 640481311. The reversal of 640481287 is 782184046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640481287 - 2¹⁵ = 640448519 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640482287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320240643 + 320240644.

It is an arithmetic number, because the mean of its divisors is an integer number (320240644).

Almost surely, 2^640481287 is an apocalyptic number.

640481287 is a deficient number, since it is larger than the sum of its proper divisors (1).

640481287 is an equidigital number, since it uses as much as digits as its factorization.

640481287 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 86016, while the sum is 40.

The square root of 640481287 is about 25307.7317632379. The cubic root of 640481287 is about 861.9898430121.

The spelling of 640481287 in words is "six hundred forty million, four hundred eighty-one thousand, two hundred eighty-seven".