521546784821 has 2 divisors, whose sum is σ = 521546784822. Its totient is φ = 521546784820.

The previous prime is 521546784793. The next prime is 521546784851. The reversal of 521546784821 is 128487645125.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 465104904196 + 56441880625 = 681986^2 + 237575^2 .

It is a cyclic number.

It is not a de Polignac number, because 521546784821 - 2¹⁴ = 521546768437 is a prime.

It is a super-2 number, since 2×521546784821² (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 (521546784851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260773392410 + 260773392411.

It is an arithmetic number, because the mean of its divisors is an integer number (260773392411).

Almost surely, 2^521546784821 is an apocalyptic number.

It is an amenable number.

521546784821 is a deficient number, since it is larger than the sum of its proper divisors (1).

521546784821 is an equidigital number, since it uses as much as digits as its factorization.

521546784821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4300800, while the sum is 53.

The spelling of 521546784821 in words is "five hundred twenty-one billion, five hundred forty-six million, seven hundred eighty-four thousand, eight hundred twenty-one".