640205411 has 4 divisors (see below), whose sum is σ = 640528632. Its totient is φ = 639882192.

The previous prime is 640205407. The next prime is 640205441. The reversal of 640205411 is 114502046.

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

It is a cyclic number.

It is not a de Polignac number, because 640205411 - 2² = 640205407 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640205441) 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, 158621 + ... + 162606.

It is an arithmetic number, because the mean of its divisors is an integer number (160132158).

Almost surely, 2^640205411 is an apocalyptic number.

640205411 is a deficient number, since it is larger than the sum of its proper divisors (323221).

640205411 is a wasteful number, since it uses less digits than its factorization.

640205411 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323220.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 640205411 is about 25302.2807469999. The cubic root of 640205411 is about 861.8660629392.

Adding to 640205411 its reverse (114502046), we get a palindrome (754707457).

The spelling of 640205411 in words is "six hundred forty million, two hundred five thousand, four hundred eleven".