653221421 has 4 divisors (see below), whose sum is σ = 670876092. Its totient is φ = 635566752.

The previous prime is 653221409. The next prime is 653221451. The reversal of 653221421 is 124122356.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 496621225 + 156600196 = 22285^2 + 12514^2 .

It is a cyclic number.

It is not a de Polignac number, because 653221421 - 2⁶ = 653221357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (653221451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8827280 + ... + 8827353.

It is an arithmetic number, because the mean of its divisors is an integer number (167719023).

Almost surely, 2^653221421 is an apocalyptic number.

It is an amenable number.

653221421 is a deficient number, since it is larger than the sum of its proper divisors (17654671).

653221421 is a wasteful number, since it uses less digits than its factorization.

653221421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17654670.

The product of its digits is 2880, while the sum is 26.

The square root of 653221421 is about 25558.1967478146. The cubic root of 653221421 is about 867.6677840720.

Adding to 653221421 its reverse (124122356), we get a palindrome (777343777).

The spelling of 653221421 in words is "six hundred fifty-three million, two hundred twenty-one thousand, four hundred twenty-one".