21530425 has 12 divisors (see below), whose sum is σ = 30511936. Its totient is φ = 14763600.

The previous prime is 21530413. The next prime is 21530447. The reversal of 21530425 is 52403512.

It is not a de Polignac number, because 21530425 - 2⁵ = 21530393 is a prime.

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21530396 and 21530405.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 61341 + ... + 61690.

Almost surely, 2^21530425 is an apocalyptic number.

21530425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21530425 is a deficient number, since it is larger than the sum of its proper divisors (8981511).

21530425 is a wasteful number, since it uses less digits than its factorization.

21530425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123048 (or 123043 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 21530425 is about 4640.0889000104. The cubic root of 21530425 is about 278.1959912203.

Adding to 21530425 its reverse (52403512), we get a palindrome (73933937).

The spelling of 21530425 in words is "twenty-one million, five hundred thirty thousand, four hundred twenty-five".