211521253423 has 4 divisors (see below), whose sum is σ = 212325517008. Its totient is φ = 210716989840.

The previous prime is 211521253399. The next prime is 211521253439. The reversal of 211521253423 is 324352125112.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211521253423 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 (211521253123) 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, 402131398 + ... + 402131923.

It is an arithmetic number, because the mean of its divisors is an integer number (53081379252).

Almost surely, 2^211521253423 is an apocalyptic number.

211521253423 is a deficient number, since it is larger than the sum of its proper divisors (804263585).

211521253423 is an equidigital number, since it uses as much as digits as its factorization.

211521253423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 804263584.

The product of its digits is 14400, while the sum is 31.

Adding to 211521253423 its reverse (324352125112), we get a palindrome (535873378535).

The spelling of 211521253423 in words is "two hundred eleven billion, five hundred twenty-one million, two hundred fifty-three thousand, four hundred twenty-three".