21240255224 has 16 divisors (see below), whose sum is σ = 40901843400. Its totient is φ = 10333096992.

The previous prime is 21240255221. The next prime is 21240255227. The reversal of 21240255224 is 42255204212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21240255221) and next prime (21240255227).

It is a super-2 number, since 2×21240255224² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21240255221) 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, 35878514 + ... + 35879105.

Almost surely, 2^21240255224 is an apocalyptic number.

It is an amenable number.

21240255224 is a deficient number, since it is larger than the sum of its proper divisors (19661588176).

21240255224 is a wasteful number, since it uses less digits than its factorization.

21240255224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71757662 (or 71757658 counting only the distinct ones).

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

Adding to 21240255224 its reverse (42255204212), we get a palindrome (63495459436).

The spelling of 21240255224 in words is "twenty-one billion, two hundred forty million, two hundred fifty-five thousand, two hundred twenty-four".