21930225 has 24 divisors (see below), whose sum is σ = 36426240. Its totient is φ = 11641920.

The previous prime is 21930157. The next prime is 21930269. The reversal of 21930225 is 52203912.

It is not a de Polignac number, because 21930225 - 2¹⁷ = 21799153 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21930195 and 21930204.

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, 19632 + ... + 20718.

It is an arithmetic number, because the mean of its divisors is an integer number (1517760).

Almost surely, 2^21930225 is an apocalyptic number.

21930225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21930225 is a deficient number, since it is larger than the sum of its proper divisors (14496015).

21930225 is a wasteful number, since it uses less digits than its factorization.

21930225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1369 (or 1364 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 21930225 is about 4682.9718128556. The cubic root of 21930225 is about 279.9073885894.

It can be divided in two parts, 21930 and 225, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 21930225 in words is "twenty-one million, nine hundred thirty thousand, two hundred twenty-five".