21202123253 has 4 divisors (see below), whose sum is σ = 21470504640. Its totient is φ = 20933741868.

The previous prime is 21202123193. The next prime is 21202123277. The reversal of 21202123253 is 35232120212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21202123253 - 2¹² = 21202119157 is a prime.

It is a super-3 number, since 3×21202123253³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202123153) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 134190575 + ... + 134190732.

It is an arithmetic number, because the mean of its divisors is an integer number (5367626160).

Almost surely, 2^21202123253 is an apocalyptic number.

It is an amenable number.

21202123253 is a deficient number, since it is larger than the sum of its proper divisors (268381387).

21202123253 is an equidigital number, since it uses as much as digits as its factorization.

21202123253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268381386.

The product of its (nonzero) digits is 1440, while the sum is 23.

Adding to 21202123253 its reverse (35232120212), we get a palindrome (56434243465).

The spelling of 21202123253 in words is "twenty-one billion, two hundred two million, one hundred twenty-three thousand, two hundred fifty-three".