21842425 has 12 divisors (see below), whose sum is σ = 29547216. Its totient is φ = 15885200.

The previous prime is 21842393. The next prime is 21842441. The reversal of 21842425 is 52424812.

It is not a de Polignac number, because 21842425 - 2⁵ = 21842393 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21842393 and 21842402.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 39439 + ... + 39988.

It is an arithmetic number, because the mean of its divisors is an integer number (2462268).

Almost surely, 2^21842425 is an apocalyptic number.

21842425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21842425 is a deficient number, since it is larger than the sum of its proper divisors (7704791).

21842425 is a wasteful number, since it uses less digits than its factorization.

21842425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79448 (or 79443 counting only the distinct ones).

The product of its digits is 5120, while the sum is 28.

The square root of 21842425 is about 4673.5880220661. The cubic root of 21842425 is about 279.5333425831.

The spelling of 21842425 in words is "twenty-one million, eight hundred forty-two thousand, four hundred twenty-five".