21603125 has 24 divisors (see below), whose sum is σ = 27998208. Its totient is φ = 16650000.

The previous prime is 21603097. The next prime is 21603137. The reversal of 21603125 is 52130612.

It is not a de Polignac number, because 21603125 - 2²⁰ = 20554549 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21603097 and 21603106.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 96764 + ... + 96986.

It is an arithmetic number, because the mean of its divisors is an integer number (1166592).

Almost surely, 2^21603125 is an apocalyptic number.

21603125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21603125 is a deficient number, since it is larger than the sum of its proper divisors (6395083).

21603125 is an frugal number, since it uses more digits than its factorization.

21603125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279 (or 259 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21603125 is about 4647.9161997609. The cubic root of 21603125 is about 278.5087598924.

Adding to 21603125 its reverse (52130612), we get a palindrome (73733737).

The spelling of 21603125 in words is "twenty-one million, six hundred three thousand, one hundred twenty-five".