21123252342 has 24 divisors (see below), whose sum is σ = 45810633960. Its totient is φ = 7034378400.

The previous prime is 21123252323. The next prime is 21123252349. The reversal of 21123252342 is 24325232112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123252349) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 539367 + ... + 577202.

It is an arithmetic number, because the mean of its divisors is an integer number (1908776415).

Almost surely, 2^21123252342 is an apocalyptic number.

21123252342 is an abundant number, since it is smaller than the sum of its proper divisors (24687381618).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21123252342 is a wasteful number, since it uses less digits than its factorization.

21123252342 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1117628 (or 1117625 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

Adding to 21123252342 its reverse (24325232112), we get a palindrome (45448484454).

The spelling of 21123252342 in words is "twenty-one billion, one hundred twenty-three million, two hundred fifty-two thousand, three hundred forty-two".