251222021 has 2 divisors, whose sum is σ = 251222022. Its totient is φ = 251222020.

The previous prime is 251222017. The next prime is 251222051. The reversal of 251222021 is 120222152.

251222021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 250873921 + 348100 = 15839^2 + 590^2 .

It is a cyclic number.

It is not a de Polignac number, because 251222021 - 2² = 251222017 is a prime.

It is a super-2 number, since 2×251222021² = 126225007670648882, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251222051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125611010 + 125611011.

It is an arithmetic number, because the mean of its divisors is an integer number (125611011).

Almost surely, 2^251222021 is an apocalyptic number.

It is an amenable number.

251222021 is a deficient number, since it is larger than the sum of its proper divisors (1).

251222021 is an equidigital number, since it uses as much as digits as its factorization.

251222021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 251222021 is about 15849.9848895827. The cubic root of 251222021 is about 630.9852903645.

Adding to 251222021 its reverse (120222152), we get a palindrome (371444173).

The spelling of 251222021 in words is "two hundred fifty-one million, two hundred twenty-two thousand, twenty-one".