640951957801 has 4 divisors (see below), whose sum is σ = 641002482900. Its totient is φ = 640901432704.

The previous prime is 640951957787. The next prime is 640951957823. The reversal of 640951957801 is 108759159046.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 202118579776 + 438833378025 = 449576^2 + 662445^2 .

It is a cyclic number.

It is not a de Polignac number, because 640951957801 - 2¹¹ = 640951955753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640951957201) 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, 25243516 + ... + 25268893.

It is an arithmetic number, because the mean of its divisors is an integer number (160250620725).

Almost surely, 2^640951957801 is an apocalyptic number.

It is an amenable number.

640951957801 is a deficient number, since it is larger than the sum of its proper divisors (50525099).

640951957801 is a wasteful number, since it uses less digits than its factorization.

640951957801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50525098.

The product of its (nonzero) digits is 2721600, while the sum is 55.

The spelling of 640951957801 in words is "six hundred forty billion, nine hundred fifty-one million, nine hundred fifty-seven thousand, eight hundred one".