21040243250 has 64 divisors (see below), whose sum is σ = 43319937024. Its totient is φ = 7603358400.

The previous prime is 21040243243. The next prime is 21040243253. The reversal of 21040243250 is 5234204012.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21040243253) 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, 83879 + ... + 221621.

It is an arithmetic number, because the mean of its divisors is an integer number (676874016).

Almost surely, 2^21040243250 is an apocalyptic number.

21040243250 is an abundant number, since it is smaller than the sum of its proper divisors (22279693774).

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

21040243250 is a wasteful number, since it uses less digits than its factorization.

21040243250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137820 (or 137810 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 23.

Adding to 21040243250 its reverse (5234204012), we get a palindrome (26274447262).

The spelling of 21040243250 in words is "twenty-one billion, forty million, two hundred forty-three thousand, two hundred fifty".