640261342651 has 8 divisors (see below), whose sum is σ = 731734624224. Its totient is φ = 548789904960.

The previous prime is 640261342627. The next prime is 640261342687. The reversal of 640261342651 is 156243162046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640261342651 - 2¹¹ = 640261340603 is a prime.

It is a super-2 number, since 2×640261342651² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640261342621) 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 7 ways as a sum of consecutive naturals, for example, 387141 + ... + 1195993.

It is an arithmetic number, because the mean of its divisors is an integer number (91466828028).

Almost surely, 2^640261342651 is an apocalyptic number.

640261342651 is a deficient number, since it is larger than the sum of its proper divisors (91473281573).

640261342651 is a wasteful number, since it uses less digits than its factorization.

640261342651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 921941.

The product of its (nonzero) digits is 207360, while the sum is 40.

The spelling of 640261342651 in words is "six hundred forty billion, two hundred sixty-one million, three hundred forty-two thousand, six hundred fifty-one".