21121443250 has 32 divisors (see below), whose sum is σ = 39551269680. Its totient is φ = 8446028800.

The previous prime is 21121443227. The next prime is 21121443293. The reversal of 21121443250 is 5234412112.

It can be written as a sum of positive squares in 8 ways, for example, as 27657081 + 21093786169 = 5259^2 + 145237^2 .

It is a super-2 number, since 2×21121443250² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 968466 + ... + 990034.

Almost surely, 2^21121443250 is an apocalyptic number.

21121443250 is a deficient number, since it is larger than the sum of its proper divisors (18429826430).

21121443250 is a wasteful number, since it uses less digits than its factorization.

21121443250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25503 (or 25493 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21121443250 its reverse (5234412112), we get a palindrome (26355855362).

The spelling of 21121443250 in words is "twenty-one billion, one hundred twenty-one million, four hundred forty-three thousand, two hundred fifty".