251123021201 has 4 divisors (see below), whose sum is σ = 270440176692. Its totient is φ = 231805865712.

The previous prime is 251123021143. The next prime is 251123021213. The reversal of 251123021201 is 102120321152.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18339930625 + 232783090576 = 135425^2 + 482476^2 .

It is a cyclic number.

It is not a de Polignac number, because 251123021201 - 2¹⁸ = 251122759057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251123021291) 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, 9658577726 + ... + 9658577751.

It is an arithmetic number, because the mean of its divisors is an integer number (67610044173).

Almost surely, 2^251123021201 is an apocalyptic number.

It is an amenable number.

251123021201 is a deficient number, since it is larger than the sum of its proper divisors (19317155491).

251123021201 is a wasteful number, since it uses less digits than its factorization.

251123021201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19317155490.

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 251123021201 its reverse (102120321152), we get a palindrome (353243342353).

The spelling of 251123021201 in words is "two hundred fifty-one billion, one hundred twenty-three million, twenty-one thousand, two hundred one".