421415521 has 2 divisors, whose sum is σ = 421415522. Its totient is φ = 421415520.

The previous prime is 421415513. The next prime is 421415543. The reversal of 421415521 is 125514124.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 254721600 + 166693921 = 15960^2 + 12911^2 .

It is a cyclic number.

It is not a de Polignac number, because 421415521 - 2³ = 421415513 is a prime.

It is a super-3 number, since 3×421415521³ (a number of 27 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (421415551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210707760 + 210707761.

It is an arithmetic number, because the mean of its divisors is an integer number (210707761).

Almost surely, 2^421415521 is an apocalyptic number.

It is an amenable number.

421415521 is a deficient number, since it is larger than the sum of its proper divisors (1).

421415521 is an equidigital number, since it uses as much as digits as its factorization.

421415521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1600, while the sum is 25.

The square root of 421415521 is about 20528.4076586568. The cubic root of 421415521 is about 749.7276172370.

Adding to 421415521 its reverse (125514124), we get a palindrome (546929645).

The spelling of 421415521 in words is "four hundred twenty-one million, four hundred fifteen thousand, five hundred twenty-one".