21653221202 has 18 divisors (see below), whose sum is σ = 32993085573. Its totient is φ = 10658152032.

The previous prime is 21653221201. The next prime is 21653221207. The reversal of 21653221202 is 20212235612.

It can be written as a sum of positive squares in 2 ways, for example, as 17368340521 + 4284880681 = 131789^2 + 65459^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=104051.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21653221201) 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 8 ways as a sum of consecutive naturals, for example, 13942058 + ... + 13943610.

Almost surely, 2^21653221202 is an apocalyptic number.

21653221202 is a deficient number, since it is larger than the sum of its proper divisors (11339864371).

21653221202 is an frugal number, since it uses more digits than its factorization.

21653221202 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3242 (or 1622 counting only the distinct ones).

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

Adding to 21653221202 its reverse (20212235612), we get a palindrome (41865456814).

The spelling of 21653221202 in words is "twenty-one billion, six hundred fifty-three million, two hundred twenty-one thousand, two hundred two".