21111925 has 24 divisors (see below), whose sum is σ = 27498240. Its totient is φ = 16060800.

The previous prime is 21111877. The next prime is 21111931. The reversal of 21111925 is 52911112.

It is not a de Polignac number, because 21111925 - 2¹¹ = 21109877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21111896 and 21111905.

It is a congruent number.

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, 43836 + ... + 44314.

It is an arithmetic number, because the mean of its divisors is an integer number (1145760).

Almost surely, 2^21111925 is an apocalyptic number.

21111925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21111925 is a deficient number, since it is larger than the sum of its proper divisors (6386315).

21111925 is a wasteful number, since it uses less digits than its factorization.

21111925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 573 (or 568 counting only the distinct ones).

The product of its digits is 180, while the sum is 22.

The square root of 21111925 is about 4594.7714850687. The cubic root of 21111925 is about 276.3816963843.

The spelling of 21111925 in words is "twenty-one million, one hundred eleven thousand, nine hundred twenty-five".