21628425 has 48 divisors (see below), whose sum is σ = 44024960. Its totient is φ = 9123840.

The previous prime is 21628417. The next prime is 21628427. The reversal of 21628425 is 52482612.

It is not a de Polignac number, because 21628425 - 2³ = 21628417 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21628392 and 21628401.

It is not an unprimeable number, because it can be changed into a prime (21628427) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5241 + ... + 8409.

Almost surely, 2^21628425 is an apocalyptic number.

21628425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21628425 is an abundant number, since it is smaller than the sum of its proper divisors (22396535).

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

21628425 is a wasteful number, since it uses less digits than its factorization.

21628425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3202 (or 3197 counting only the distinct ones).

The product of its digits is 7680, while the sum is 30.

The square root of 21628425 is about 4650.6370531358. The cubic root of 21628425 is about 278.6174405072.

The spelling of 21628425 in words is "twenty-one million, six hundred twenty-eight thousand, four hundred twenty-five".