21120125 has 32 divisors (see below), whose sum is σ = 29169504. Its totient is φ = 15168000.

The previous prime is 21120119. The next prime is 21120131. The reversal of 21120125 is 52102112.

It is an interprime number because it is at equal distance from previous prime (21120119) and next prime (21120131).

It can be written as a sum of positive squares in 16 ways, for example, as 20457529 + 662596 = 4523^2 + 814^2 .

It is not a de Polignac number, because 21120125 - 2⁴ = 21120109 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 66467 + ... + 66783.

It is an arithmetic number, because the mean of its divisors is an integer number (911547).

Almost surely, 2^21120125 is an apocalyptic number.

21120125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21120125 is a deficient number, since it is larger than the sum of its proper divisors (8049379).

21120125 is a wasteful number, since it uses less digits than its factorization.

21120125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 386 (or 376 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 21120125 is about 4595.6637170272. The cubic root of 21120125 is about 276.4174745295.

Adding to 21120125 its reverse (52102112), we get a palindrome (73222237).

The spelling of 21120125 in words is "twenty-one million, one hundred twenty thousand, one hundred twenty-five".