21205425224 has 16 divisors (see below), whose sum is σ = 40046218800. Its totient is φ = 10526433552.

The previous prime is 21205425223. The next prime is 21205425257. The reversal of 21205425224 is 42252450212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21205425223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9533702 + ... + 9535925.

It is an arithmetic number, because the mean of its divisors is an integer number (2502888675).

Almost surely, 2^21205425224 is an apocalyptic number.

It is an amenable number.

21205425224 is a deficient number, since it is larger than the sum of its proper divisors (18840793576).

21205425224 is a wasteful number, since it uses less digits than its factorization.

21205425224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19069772 (or 19069768 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 29.

Adding to 21205425224 its reverse (42252450212), we get a palindrome (63457875436).

The spelling of 21205425224 in words is "twenty-one billion, two hundred five million, four hundred twenty-five thousand, two hundred twenty-four".