21102123025 has 24 divisors (see below), whose sum is σ = 26328425984. Its totient is φ = 16777497600.

The previous prime is 21102123019. The next prime is 21102123047. The reversal of 21102123025 is 52032120112.

It is a de Polignac number, because none of the positive numbers 2^k-21102123025 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21102122993 and 21102123011.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7559380 + ... + 7562170.

Almost surely, 2^21102123025 is an apocalyptic number.

21102123025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21102123025 is a deficient number, since it is larger than the sum of its proper divisors (5226302959).

21102123025 is a wasteful number, since it uses less digits than its factorization.

21102123025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4561 (or 4556 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

Adding to 21102123025 its reverse (52032120112), we get a palindrome (73134243137).

The spelling of 21102123025 in words is "twenty-one billion, one hundred two million, one hundred twenty-three thousand, twenty-five".