21153253121 has 32 divisors (see below), whose sum is σ = 28449792000. Its totient is φ = 15189295680.

The previous prime is 21153253097. The next prime is 21153253141. The reversal of 21153253121 is 12135235112.

It is a de Polignac number, because none of the positive numbers 2^k-21153253121 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21153253141) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 581960 + ... + 617238.

It is an arithmetic number, because the mean of its divisors is an integer number (889056000).

Almost surely, 2^21153253121 is an apocalyptic number.

It is an amenable number.

21153253121 is a deficient number, since it is larger than the sum of its proper divisors (7296538879).

21153253121 is a wasteful number, since it uses less digits than its factorization.

21153253121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35909.

The product of its digits is 1800, while the sum is 26.

Adding to 21153253121 its reverse (12135235112), we get a palindrome (33288488233).

The spelling of 21153253121 in words is "twenty-one billion, one hundred fifty-three million, two hundred fifty-three thousand, one hundred twenty-one".