640426424631 has 48 divisors (see below), whose sum is σ = 986749231104. Its totient is φ = 361907203392.

The previous prime is 640426424597. The next prime is 640426424641. The reversal of 640426424631 is 136424624046.

It is a happy number.

It is not a de Polignac number, because 640426424631 - 2¹³ = 640426416439 is a prime.

It is a super-2 number, since 2×640426424631² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640426424641) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 391218745 + ... + 391220381.

It is an arithmetic number, because the mean of its divisors is an integer number (20557275648).

Almost surely, 2^640426424631 is an apocalyptic number.

640426424631 is a deficient number, since it is larger than the sum of its proper divisors (346322806473).

640426424631 is a wasteful number, since it uses less digits than its factorization.

640426424631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2540 (or 2157 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 42.

The spelling of 640426424631 in words is "six hundred forty billion, four hundred twenty-six million, four hundred twenty-four thousand, six hundred thirty-one".