21450340252 has 24 divisors (see below), whose sum is σ = 41025559680. Its totient is φ = 9732318960.

The previous prime is 21450340213. The next prime is 21450340309. The reversal of 21450340252 is 25204305412.

It is a self number, because there is not a number n which added to its sum of digits gives 21450340252.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 421552 + ... + 469687.

It is an arithmetic number, because the mean of its divisors is an integer number (1709398320).

Almost surely, 2^21450340252 is an apocalyptic number.

21450340252 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21450340252 is a deficient number, since it is larger than the sum of its proper divisors (19575219428).

21450340252 is a wasteful number, since it uses less digits than its factorization.

21450340252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891801 (or 891799 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 28.

Adding to 21450340252 its reverse (25204305412), we get a palindrome (46654645664).

The spelling of 21450340252 in words is "twenty-one billion, four hundred fifty million, three hundred forty thousand, two hundred fifty-two".