640401213 has 32 divisors (see below), whose sum is σ = 943119360. Its totient is φ = 384721920.

The previous prime is 640401211. The next prime is 640401253. The reversal of 640401213 is 312104046.

It is not a de Polignac number, because 640401213 - 2¹ = 640401211 is a prime.

It is a super-2 number, since 2×640401213² = 820227427223742738, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 640401213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640401211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 251758 + ... + 254288.

It is an arithmetic number, because the mean of its divisors is an integer number (29472480).

Almost surely, 2^640401213 is an apocalyptic number.

It is an amenable number.

640401213 is a deficient number, since it is larger than the sum of its proper divisors (302718147).

640401213 is a wasteful number, since it uses less digits than its factorization.

640401213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2769.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 640401213 is about 25306.1497071364. The cubic root of 640401213 is about 861.9539190630.

Adding to 640401213 its reverse (312104046), we get a palindrome (952505259).

The spelling of 640401213 in words is "six hundred forty million, four hundred one thousand, two hundred thirteen".