521002421 has 2 divisors, whose sum is σ = 521002422. Its totient is φ = 521002420.

The previous prime is 521002411. The next prime is 521002481. The reversal of 521002421 is 124200125.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 294499921 + 226502500 = 17161^2 + 15050^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-521002421 is a prime.

It is a super-2 number, since 2×521002421² = 542887045375722482, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 521002421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521002411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260501210 + 260501211.

It is an arithmetic number, because the mean of its divisors is an integer number (260501211).

Almost surely, 2^521002421 is an apocalyptic number.

It is an amenable number.

521002421 is a deficient number, since it is larger than the sum of its proper divisors (1).

521002421 is an equidigital number, since it uses as much as digits as its factorization.

521002421 is an odious number, because the sum of its binary digits is odd.

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

The square root of 521002421 is about 22825.4774539329. The cubic root of 521002421 is about 804.6615456694.

Adding to 521002421 its reverse (124200125), we get a palindrome (645202546).

The spelling of 521002421 in words is "five hundred twenty-one million, two thousand, four hundred twenty-one".