646753943551 has 4 divisors (see below), whose sum is σ = 647762920704. Its totient is φ = 645744966400.

The previous prime is 646753943531. The next prime is 646753943597. The reversal of 646753943551 is 155349357646.

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 646753943551 - 2¹¹ = 646753941503 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646753943531) 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, 504487615 + ... + 504488896.

It is an arithmetic number, because the mean of its divisors is an integer number (161940730176).

Almost surely, 2^646753943551 is an apocalyptic number.

646753943551 is a deficient number, since it is larger than the sum of its proper divisors (1008977153).

646753943551 is a wasteful number, since it uses less digits than its factorization.

646753943551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1008977152.

The product of its digits is 40824000, while the sum is 58.

The spelling of 646753943551 in words is "six hundred forty-six billion, seven hundred fifty-three million, nine hundred forty-three thousand, five hundred fifty-one".