640043235 has 64 divisors (see below), whose sum is σ = 1230082560. Its totient is φ = 313891200.

The previous prime is 640043231. The next prime is 640043237. The reversal of 640043235 is 532340046.

It is not a de Polignac number, because 640043235 - 2² = 640043231 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 640043199 and 640043208.

It is not an unprimeable number, because it can be changed into a prime (640043231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 608460 + ... + 609510.

It is an arithmetic number, because the mean of its divisors is an integer number (19220040).

Almost surely, 2^640043235 is an apocalyptic number.

640043235 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

640043235 is a deficient number, since it is larger than the sum of its proper divisors (590039325).

640043235 is a wasteful number, since it uses less digits than its factorization.

640043235 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1425 (or 1419 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 27.

The square root of 640043235 is about 25299.0757736325. The cubic root of 640043235 is about 861.7932811974.

The spelling of 640043235 in words is "six hundred forty million, forty-three thousand, two hundred thirty-five".