421545521 has 2 divisors, whose sum is σ = 421545522. Its totient is φ = 421545520.

The previous prime is 421545511. The next prime is 421545529. The reversal of 421545521 is 125545124.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 403567921 + 17977600 = 20089^2 + 4240^2 .

It is a cyclic number.

It is not a de Polignac number, because 421545521 - 2²² = 417351217 is a prime.

It is a super-2 number, since 2×421545521² = 355401252550322882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (421545529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210772760 + 210772761.

It is an arithmetic number, because the mean of its divisors is an integer number (210772761).

Almost surely, 2^421545521 is an apocalyptic number.

It is an amenable number.

421545521 is a deficient number, since it is larger than the sum of its proper divisors (1).

421545521 is an equidigital number, since it uses as much as digits as its factorization.

421545521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8000, while the sum is 29.

The square root of 421545521 is about 20531.5737584823. The cubic root of 421545521 is about 749.8047023347.

The spelling of 421545521 in words is "four hundred twenty-one million, five hundred forty-five thousand, five hundred twenty-one".