640268783 has 16 divisors (see below), whose sum is σ = 840272640. Its totient is φ = 472651200.

The previous prime is 640268771. The next prime is 640268789. The reversal of 640268783 is 387862046.

It is not a de Polignac number, because 640268783 - 2¹⁰ = 640267759 is a prime.

It is a super-2 number, since 2×640268783² = 819888228968602178, which contains 22 as substring.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640268789) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 217358 + ... + 220283.

It is an arithmetic number, because the mean of its divisors is an integer number (52517040).

Almost surely, 2^640268783 is an apocalyptic number.

640268783 is a deficient number, since it is larger than the sum of its proper divisors (200003857).

640268783 is a wasteful number, since it uses less digits than its factorization.

640268783 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437678.

The product of its (nonzero) digits is 387072, while the sum is 44.

The square root of 640268783 is about 25303.5330141860. The cubic root of 640268783 is about 861.8944998404.

The spelling of 640268783 in words is "six hundred forty million, two hundred sixty-eight thousand, seven hundred eighty-three".