655220421 has 10 divisors (see below), whose sum is σ = 978786182. Its totient is φ = 436813560.

The previous prime is 655220413. The next prime is 655220441. The reversal of 655220421 is 124022556.

655220421 is a `hidden beast` number, since 655 + 2 + 2 + 0 + 4 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 353816100 + 301404321 = 18810^2 + 17361^2 .

It is not a de Polignac number, because 655220421 - 2³ = 655220413 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (655220441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 4044490 + ... + 4044651.

Almost surely, 2^655220421 is an apocalyptic number.

It is an amenable number.

655220421 is a deficient number, since it is larger than the sum of its proper divisors (323565761).

655220421 is an equidigital number, since it uses as much as digits as its factorization.

655220421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8089153 (or 8089144 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 655220421 is about 25597.2737024864. The cubic root of 655220421 is about 868.5519669657.

Adding to 655220421 its reverse (124022556), we get a palindrome (779242977).

The spelling of 655220421 in words is "six hundred fifty-five million, two hundred twenty thousand, four hundred twenty-one".