21144025 has 12 divisors (see below), whose sum is σ = 29964352. Its totient is φ = 14498640.

The previous prime is 21143999. The next prime is 21144029. The reversal of 21144025 is 52044112.

It is not a de Polignac number, because 21144025 - 2⁷ = 21143897 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21143993 and 21144011.

It is not an unprimeable number, because it can be changed into a prime (21144029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60237 + ... + 60586.

Almost surely, 2^21144025 is an apocalyptic number.

21144025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21144025 is a deficient number, since it is larger than the sum of its proper divisors (8820327).

21144025 is a wasteful number, since it uses less digits than its factorization.

21144025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120840 (or 120835 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21144025 is about 4598.2632591012. The cubic root of 21144025 is about 276.5217019308.

Adding to 21144025 its reverse (52044112), we get a palindrome (73188137).

The spelling of 21144025 in words is "twenty-one million, one hundred forty-four thousand, twenty-five".