21121152240225 has 12 divisors (see below), whose sum is σ = 34920305037296. Its totient is φ = 11264614528080.

The previous prime is 21121152240211. The next prime is 21121152240247. The reversal of 21121152240225 is 52204225112112.

It is a happy number.

It is not a de Polignac number, because 21121152240225 - 2¹⁴ = 21121152223841 is a prime.

It is a super-2 number, since 2×21121152240225² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121152240192 and 21121152240201.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 140807681527 + ... + 140807681676.

Almost surely, 2^{21121152240225} is an apocalyptic number.

21121152240225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21121152240225 is a deficient number, since it is larger than the sum of its proper divisors (13799152797071).

21121152240225 is a wasteful number, since it uses less digits than its factorization.

21121152240225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281615363216 (or 281615363211 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 30.

Adding to 21121152240225 its reverse (52204225112112), we get a palindrome (73325377352337).

The spelling of 21121152240225 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred fifty-two million, two hundred forty thousand, two hundred twenty-five".