21240223430 has 16 divisors (see below), whose sum is σ = 39164900544. Its totient is φ = 8288867520.

The previous prime is 21240223423. The next prime is 21240223451. The reversal of 21240223430 is 3432204212.

It is a super-2 number, since 2×21240223430² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21240223396 and 21240223405.

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, 25902302 + ... + 25903121.

It is an arithmetic number, because the mean of its divisors is an integer number (2447806284).

Almost surely, 2^21240223430 is an apocalyptic number.

21240223430 is a deficient number, since it is larger than the sum of its proper divisors (17924677114).

21240223430 is a wasteful number, since it uses less digits than its factorization.

21240223430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51805471.

The product of its (nonzero) digits is 2304, while the sum is 23.

Adding to 21240223430 its reverse (3432204212), we get a palindrome (24672427642).

The spelling of 21240223430 in words is "twenty-one billion, two hundred forty million, two hundred twenty-three thousand, four hundred thirty".