21819625 has 16 divisors (see below), whose sum is σ = 27415440. Its totient is φ = 17337600.

The previous prime is 21819601. The next prime is 21819643. The reversal of 21819625 is 52691812.

It can be written as a sum of positive squares in 8 ways, for example, as 4380649 + 17438976 = 2093^2 + 4176^2 .

It is not a de Polignac number, because 21819625 - 2¹¹ = 21817577 is a prime.

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, 21121 + ... + 22129.

It is an arithmetic number, because the mean of its divisors is an integer number (1713465).

Almost surely, 2^21819625 is an apocalyptic number.

21819625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21819625 is a deficient number, since it is larger than the sum of its proper divisors (5595815).

21819625 is a wasteful number, since it uses less digits than its factorization.

21819625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1197 (or 1187 counting only the distinct ones).

The product of its digits is 8640, while the sum is 34.

The square root of 21819625 is about 4671.1481457988. The cubic root of 21819625 is about 279.4360460133.

The spelling of 21819625 in words is "twenty-one million, eight hundred nineteen thousand, six hundred twenty-five".