21285425 has 12 divisors (see below), whose sum is σ = 30164736. Its totient is φ = 14595600.

The previous prime is 21285421. The next prime is 21285463. The reversal of 21285425 is 52458212.

It is not a de Polignac number, because 21285425 - 2² = 21285421 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21285421) 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, 60641 + ... + 60990.

It is an arithmetic number, because the mean of its divisors is an integer number (2513728).

Almost surely, 2^21285425 is an apocalyptic number.

21285425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21285425 is a deficient number, since it is larger than the sum of its proper divisors (8879311).

21285425 is a wasteful number, since it uses less digits than its factorization.

21285425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121648 (or 121643 counting only the distinct ones).

The product of its digits is 6400, while the sum is 29.

The square root of 21285425 is about 4613.6130093453. The cubic root of 21285425 is about 277.1367429910.

The spelling of 21285425 in words is "twenty-one million, two hundred eighty-five thousand, four hundred twenty-five".