640303645066251 has 4 divisors (see below), whose sum is σ = 853738193421672. Its totient is φ = 426869096710832.

The previous prime is 640303645066249. The next prime is 640303645066273. The reversal of 640303645066251 is 152660546303046.

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

It is a cyclic number.

It is not a de Polignac number, because 640303645066251 - 2¹ = 640303645066249 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640303645066194 and 640303645066203.

It is not an unprimeable number, because it can be changed into a prime (640303645062251) 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 3 ways as a sum of consecutive naturals, for example, 106717274177706 + ... + 106717274177711.

It is an arithmetic number, because the mean of its divisors is an integer number (213434548355418).

Almost surely, 2^{640303645066251} is an apocalyptic number.

640303645066251 is a deficient number, since it is larger than the sum of its proper divisors (213434548355421).

640303645066251 is a wasteful number, since it uses less digits than its factorization.

640303645066251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213434548355420.

The product of its (nonzero) digits is 9331200, while the sum is 51.

The spelling of 640303645066251 in words is "six hundred forty trillion, three hundred three billion, six hundred forty-five million, sixty-six thousand, two hundred fifty-one".