21444625 has 16 divisors (see below), whose sum is σ = 27930240. Its totient is φ = 16407600.

The previous prime is 21444613. The next prime is 21444641. The reversal of 21444625 is 52644412.

It is not a de Polignac number, because 21444625 - 2⁵ = 21444593 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21444593 and 21444602.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 855 + ... + 6604.

It is an arithmetic number, because the mean of its divisors is an integer number (1745640).

Almost surely, 2^21444625 is an apocalyptic number.

21444625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21444625 is a deficient number, since it is larger than the sum of its proper divisors (6485615).

21444625 is an equidigital number, since it uses as much as digits as its factorization.

21444625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7497 (or 7487 counting only the distinct ones).

The product of its digits is 7680, while the sum is 28.

The square root of 21444625 is about 4630.8341581188. The cubic root of 21444625 is about 277.8259568283.

The spelling of 21444625 in words is "twenty-one million, four hundred forty-four thousand, six hundred twenty-five".