21404625 has 32 divisors (see below), whose sum is σ = 38862720. Its totient is φ = 10376000.

The previous prime is 21404623. The next prime is 21404653. The reversal of 21404625 is 52640412.

It is not a de Polignac number, because 21404625 - 2¹ = 21404623 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21404595 and 21404604.

It is not an unprimeable number, because it can be changed into a prime (21404623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1531 + ... + 6719.

It is an arithmetic number, because the mean of its divisors is an integer number (1214460).

Almost surely, 2^21404625 is an apocalyptic number.

21404625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21404625 is a deficient number, since it is larger than the sum of its proper divisors (17458095).

21404625 is a wasteful number, since it uses less digits than its factorization.

21404625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5218 (or 5208 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 21404625 is about 4626.5132659488. The cubic root of 21404625 is about 277.6531092415.

The spelling of 21404625 in words is "twenty-one million, four hundred four thousand, six hundred twenty-five".