251224434421 has 2 divisors, whose sum is σ = 251224434422. Its totient is φ = 251224434420.

The previous prime is 251224434371. The next prime is 251224434427. The reversal of 251224434421 is 124434422152.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 236209608196 + 15014826225 = 486014^2 + 122535^2 .

It is a cyclic number.

It is not a de Polignac number, because 251224434421 - 2¹¹ = 251224432373 is a prime.

It is a super-2 number, since 2×251224434421² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (251224434427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125612217210 + 125612217211.

It is an arithmetic number, because the mean of its divisors is an integer number (125612217211).

Almost surely, 2^251224434421 is an apocalyptic number.

It is an amenable number.

251224434421 is a deficient number, since it is larger than the sum of its proper divisors (1).

251224434421 is an equidigital number, since it uses as much as digits as its factorization.

251224434421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 61440, while the sum is 34.

Adding to 251224434421 its reverse (124434422152), we get a palindrome (375658856573).

The spelling of 251224434421 in words is "two hundred fifty-one billion, two hundred twenty-four million, four hundred thirty-four thousand, four hundred twenty-one".