21673625 has 16 divisors (see below), whose sum is σ = 27714960. Its totient is φ = 16912000.

The previous prime is 21673577. The next prime is 21673633. The reversal of 21673625 is 52637612.

It can be written as a sum of positive squares in 8 ways, for example, as 5456896 + 16216729 = 2336^2 + 4027^2 .

It is not a de Polignac number, because 21673625 - 2¹⁶ = 21608089 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21673591 and 21673600.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 3011 + ... + 7239.

It is an arithmetic number, because the mean of its divisors is an integer number (1732185).

Almost surely, 2^21673625 is an apocalyptic number.

21673625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21673625 is a deficient number, since it is larger than the sum of its proper divisors (6041335).

21673625 is an equidigital number, since it uses as much as digits as its factorization.

21673625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4285 (or 4275 counting only the distinct ones).

The product of its digits is 15120, while the sum is 32.

The square root of 21673625 is about 4655.4940661545. The cubic root of 21673625 is about 278.8113943074.

The spelling of 21673625 in words is "twenty-one million, six hundred seventy-three thousand, six hundred twenty-five".