640863567 has 12 divisors (see below), whose sum is σ = 933885264. Its totient is φ = 423460800.

The previous prime is 640863557. The next prime is 640863571. The reversal of 640863567 is 765368046.

640863567 is a `hidden beast` number, since 6 + 4 + 0 + 8 + 635 + 6 + 7 = 666.

It is not a de Polignac number, because 640863567 - 2¹¹ = 640861519 is a prime.

It is a super-2 number, since 2×640863567² = 821412223015926978, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640863557) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 314059 + ... + 316092.

It is an arithmetic number, because the mean of its divisors is an integer number (77823772).

Almost surely, 2^640863567 is an apocalyptic number.

640863567 is a deficient number, since it is larger than the sum of its proper divisors (293021697).

640863567 is a wasteful number, since it uses less digits than its factorization.

640863567 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 630270 (or 630267 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The square root of 640863567 is about 25315.2832692032. The cubic root of 640863567 is about 862.1613057052.

The spelling of 640863567 in words is "six hundred forty million, eight hundred sixty-three thousand, five hundred sixty-seven".