421620561 has 12 divisors (see below), whose sum is σ = 615038580. Its totient is φ = 278296800.

The previous prime is 421620533. The next prime is 421620581. The reversal of 421620561 is 165026124.

421620561 is a `hidden beast` number, since 42 + 1 + 62 + 0 + 561 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 176384961 + 245235600 = 13281^2 + 15660^2 .

It is not a de Polignac number, because 421620561 - 2¹⁷ = 421489489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (421620581) 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 in 11 ways as a sum of consecutive naturals, for example, 231006 + ... + 232823.

It is an arithmetic number, because the mean of its divisors is an integer number (51253215).

Almost surely, 2^421620561 is an apocalyptic number.

It is an amenable number.

421620561 is a deficient number, since it is larger than the sum of its proper divisors (193418019).

421620561 is a wasteful number, since it uses less digits than its factorization.

421620561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 463936 (or 463933 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 421620561 is about 20533.4011064899. The cubic root of 421620561 is about 749.8491910109.

Adding to 421620561 its reverse (165026124), we get a palindrome (586646685).

The spelling of 421620561 in words is "four hundred twenty-one million, six hundred twenty thousand, five hundred sixty-one".