646242723451 has 4 divisors (see below), whose sum is σ = 695953702192. Its totient is φ = 596531744712.

The previous prime is 646242723443. The next prime is 646242723479. The reversal of 646242723451 is 154327242646.

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 646242723451 - 2³ = 646242723443 is a prime.

It is a super-2 number, since 2×646242723451² (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 (646242723151) 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, 24855489351 + ... + 24855489376.

It is an arithmetic number, because the mean of its divisors is an integer number (173988425548).

Almost surely, 2^646242723451 is an apocalyptic number.

646242723451 is a deficient number, since it is larger than the sum of its proper divisors (49710978741).

646242723451 is a wasteful number, since it uses less digits than its factorization.

646242723451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49710978740.

The product of its digits is 1935360, while the sum is 46.

The spelling of 646242723451 in words is "six hundred forty-six billion, two hundred forty-two million, seven hundred twenty-three thousand, four hundred fifty-one".