251421525643 has 4 divisors (see below), whose sum is σ = 251425878400. Its totient is φ = 251417172888.

The previous prime is 251421525629. The next prime is 251421525671. The reversal of 251421525643 is 346525124152.

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 251421525643 - 2⁵ = 251421525611 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 251421525596 and 251421525605.

It is not an unprimeable number, because it can be changed into a prime (251421525613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2088555 + ... + 2205652.

It is an arithmetic number, because the mean of its divisors is an integer number (62856469600).

Almost surely, 2^251421525643 is an apocalyptic number.

251421525643 is a deficient number, since it is larger than the sum of its proper divisors (4352757).

251421525643 is an equidigital number, since it uses as much as digits as its factorization.

251421525643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4352756.

The product of its digits is 288000, while the sum is 40.

Adding to 251421525643 its reverse (346525124152), we get a palindrome (597946649795).

The spelling of 251421525643 in words is "two hundred fifty-one billion, four hundred twenty-one million, five hundred twenty-five thousand, six hundred forty-three".