643795954651 has 4 divisors (see below), whose sum is σ = 643799729304. Its totient is φ = 643792180000.

The previous prime is 643795954589. The next prime is 643795954667. The reversal of 643795954651 is 156459597346.

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 643795954651 - 2¹³ = 643795946459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643795955651) 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, 1618750 + ... + 1976851.

It is an arithmetic number, because the mean of its divisors is an integer number (160949932326).

Almost surely, 2^643795954651 is an apocalyptic number.

643795954651 is a deficient number, since it is larger than the sum of its proper divisors (3774653).

643795954651 is a wasteful number, since it uses less digits than its factorization.

643795954651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3774652.

The product of its digits is 122472000, while the sum is 64.

The spelling of 643795954651 in words is "six hundred forty-three billion, seven hundred ninety-five million, nine hundred fifty-four thousand, six hundred fifty-one".