642453045251 has 4 divisors (see below), whose sum is σ = 680244400872. Its totient is φ = 604661689632.

The previous prime is 642453045187. The next prime is 642453045313. The reversal of 642453045251 is 152540354246.

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 642453045251 - 2⁶ = 642453045187 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 642453045199 and 642453045208.

It is not an unprimeable number, because it can be changed into a prime (642453845251) 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, 18895677785 + ... + 18895677818.

It is an arithmetic number, because the mean of its divisors is an integer number (170061100218).

Almost surely, 2^642453045251 is an apocalyptic number.

642453045251 is a deficient number, since it is larger than the sum of its proper divisors (37791355621).

642453045251 is a wasteful number, since it uses less digits than its factorization.

642453045251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37791355620.

The product of its (nonzero) digits is 576000, while the sum is 41.

Adding to 642453045251 its reverse (152540354246), we get a palindrome (794993399497).

The spelling of 642453045251 in words is "six hundred forty-two billion, four hundred fifty-three million, forty-five thousand, two hundred fifty-one".