640964949669 has 144 divisors (see below), whose sum is σ = 1109481318400. Its totient is φ = 354953016000.

The previous prime is 640964949661. The next prime is 640964949679. The reversal of 640964949669 is 966949469046.

640964949669 is a `hidden beast` number, since 6 + 4 + 0 + 96 + 49 + 496 + 6 + 9 = 666.

It is not a de Polignac number, because 640964949669 - 2³ = 640964949661 is a prime.

It is a super-2 number, since 2×640964949669² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 640964949597 and 640964949606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640964949661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 212308842 + ... + 212311860.

Almost surely, 2^640964949669 is an apocalyptic number.

It is an amenable number.

640964949669 is a deficient number, since it is larger than the sum of its proper divisors (468516368731).

640964949669 is a wasteful number, since it uses less digits than its factorization.

640964949669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3428 (or 3414 counting only the distinct ones).

The product of its (nonzero) digits is 544195584, while the sum is 72.

The spelling of 640964949669 in words is "six hundred forty billion, nine hundred sixty-four million, nine hundred forty-nine thousand, six hundred sixty-nine".