21121002225 has 36 divisors (see below), whose sum is σ = 37841197056. Its totient is φ = 11261219040.

The previous prime is 21121002211. The next prime is 21121002233. The reversal of 21121002225 is 52220012112.

It is not a de Polignac number, because 21121002225 - 2⁸ = 21121001969 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21121002198 and 21121002207.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 880744 + ... + 904406.

Almost surely, 2^21121002225 is an apocalyptic number.

21121002225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21121002225 is a deficient number, since it is larger than the sum of its proper divisors (16720194831).

21121002225 is a wasteful number, since it uses less digits than its factorization.

21121002225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27646 (or 27638 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

Adding to 21121002225 its reverse (52220012112), we get a palindrome (73341014337).

The spelling of 21121002225 in words is "twenty-one billion, one hundred twenty-one million, two thousand, two hundred twenty-five".