21223145242 has 16 divisors (see below), whose sum is σ = 34285948200. Its totient is φ = 9794610432.

The previous prime is 21223145239. The next prime is 21223145243. The reversal of 21223145242 is 24254132212.

It can be written as a sum of positive squares in 4 ways, for example, as 15075173961 + 6147971281 = 122781^2 + 78409^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21223145242.

It is not an unprimeable number, because it can be changed into a prime (21223145243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 677134 + ... + 707782.

Almost surely, 2^21223145242 is an apocalyptic number.

21223145242 is a deficient number, since it is larger than the sum of its proper divisors (13062802958).

21223145242 is a wasteful number, since it uses less digits than its factorization.

21223145242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57297.

The product of its digits is 7680, while the sum is 28.

Adding to 21223145242 its reverse (24254132212), we get a palindrome (45477277454).

The spelling of 21223145242 in words is "twenty-one billion, two hundred twenty-three million, one hundred forty-five thousand, two hundred forty-two".