21450825 has 84 divisors (see below), whose sum is σ = 43912368. Its totient is φ = 10303200.

The previous prime is 21450811. The next prime is 21450827. The reversal of 21450825 is 52805412.

It is a happy number.

It is not a de Polignac number, because 21450825 - 2⁴ = 21450809 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21450827) by changing a digit.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 200422 + ... + 200528.

Almost surely, 2^21450825 is an apocalyptic number.

21450825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21450825 is an abundant number, since it is smaller than the sum of its proper divisors (22461543).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21450825 is a wasteful number, since it uses less digits than its factorization.

21450825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146 (or 126 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 21450825 is about 4631.5035355703. The cubic root of 21450825 is about 277.8527289597.

The spelling of 21450825 in words is "twenty-one million, four hundred fifty thousand, eight hundred twenty-five".