21240264025 has 24 divisors (see below), whose sum is σ = 26932651200. Its totient is φ = 16611710400.

The previous prime is 21240264011. The next prime is 21240264029. The reversal of 21240264025 is 52046204212.

It is a de Polignac number, because none of the positive numbers 2^k-21240264025 is a prime.

It is a super-2 number, since 2×21240264025² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21240263984 and 21240264002.

It is not an unprimeable number, because it can be changed into a prime (21240264029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 227196 + ... + 306754.

It is an arithmetic number, because the mean of its divisors is an integer number (1122193800).

Almost surely, 2^21240264025 is an apocalyptic number.

21240264025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21240264025 is a deficient number, since it is larger than the sum of its proper divisors (5692387175).

21240264025 is a wasteful number, since it uses less digits than its factorization.

21240264025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79809 (or 79804 counting only the distinct ones).

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

Adding to 21240264025 its reverse (52046204212), we get a palindrome (73286468237).

The spelling of 21240264025 in words is "twenty-one billion, two hundred forty million, two hundred sixty-four thousand, twenty-five".