521115421 has 2 divisors, whose sum is σ = 521115422. Its totient is φ = 521115420.

The previous prime is 521115403. The next prime is 521115509. The reversal of 521115421 is 124511125.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 309267396 + 211848025 = 17586^2 + 14555^2 .

It is a cyclic number.

It is not a de Polignac number, because 521115421 - 2¹³ = 521107229 is a prime.

It is a super-2 number, since 2×521115421² = 543122564008014482, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 521115392 and 521115401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521115121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260557710 + 260557711.

It is an arithmetic number, because the mean of its divisors is an integer number (260557711).

Almost surely, 2^521115421 is an apocalyptic number.

It is an amenable number.

521115421 is a deficient number, since it is larger than the sum of its proper divisors (1).

521115421 is an equidigital number, since it uses as much as digits as its factorization.

521115421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 400, while the sum is 22.

The square root of 521115421 is about 22827.9526239214. The cubic root of 521115421 is about 804.7197157010.

Adding to 521115421 its reverse (124511125), we get a palindrome (645626546).

The spelling of 521115421 in words is "five hundred twenty-one million, one hundred fifteen thousand, four hundred twenty-one".