21783225 has 12 divisors (see below), whose sum is σ = 36015056. Its totient is φ = 11617680.

The previous prime is 21783211. The next prime is 21783227. The reversal of 21783225 is 52238712.

It is not a de Polignac number, because 21783225 - 2⁹ = 21782713 is a prime.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21783192 and 21783201.

It is not an unprimeable number, because it can be changed into a prime (21783227) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 145147 + ... + 145296.

Almost surely, 2^21783225 is an apocalyptic number.

21783225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21783225 is a deficient number, since it is larger than the sum of its proper divisors (14231831).

21783225 is a wasteful number, since it uses less digits than its factorization.

21783225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 290456 (or 290451 counting only the distinct ones).

The product of its digits is 6720, while the sum is 30.

The square root of 21783225 is about 4667.2502611281. The cubic root of 21783225 is about 279.2805723144.

The spelling of 21783225 in words is "twenty-one million, seven hundred eighty-three thousand, two hundred twenty-five".