221421251730521 has 2 divisors, whose sum is σ = 221421251730522. Its totient is φ = 221421251730520.

The previous prime is 221421251730517. The next prime is 221421251730527. The reversal of 221421251730521 is 125037152124122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 173750360473600 + 47670891256921 = 13181440^2 + 6904411^2 .

It is a cyclic number.

It is not a de Polignac number, because 221421251730521 - 2² = 221421251730517 is a prime.

It is not a weakly prime, because it can be changed into another prime (221421251730527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110710625865260 + 110710625865261.

It is an arithmetic number, because the mean of its divisors is an integer number (110710625865261).

Almost surely, 2^{221421251730521} is an apocalyptic number.

It is an amenable number.

221421251730521 is a deficient number, since it is larger than the sum of its proper divisors (1).

221421251730521 is an equidigital number, since it uses as much as digits as its factorization.

221421251730521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 67200, while the sum is 38.

The spelling of 221421251730521 in words is "two hundred twenty-one trillion, four hundred twenty-one billion, two hundred fifty-one million, seven hundred thirty thousand, five hundred twenty-one".