640213043 has 4 divisors (see below), whose sum is σ = 646551888. Its totient is φ = 633874200.

The previous prime is 640213031. The next prime is 640213051. The reversal of 640213043 is 340312046.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640213043 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640218043) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3169271 + ... + 3169472.

It is an arithmetic number, because the mean of its divisors is an integer number (161637972).

Almost surely, 2^640213043 is an apocalyptic number.

640213043 is a deficient number, since it is larger than the sum of its proper divisors (6338845).

640213043 is a wasteful number, since it uses less digits than its factorization.

640213043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6338844.

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 640213043 is about 25302.4315629941. The cubic root of 640213043 is about 861.8694877440.

Adding to 640213043 its reverse (340312046), we get a palindrome (980525089).

The spelling of 640213043 in words is "six hundred forty million, two hundred thirteen thousand, forty-three".