21340625 has 12 divisors (see below), whose sum is σ = 26677980. Its totient is φ = 17070000.

The previous prime is 21340603. The next prime is 21340633. The reversal of 21340625 is 52604312.

It can be written as a sum of positive squares in 6 ways, for example, as 17272336 + 4068289 = 4156^2 + 2017^2 .

It is not a de Polignac number, because 21340625 - 2¹² = 21336529 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21340625.

It is an unprimeable number.

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, 290 + ... + 6539.

It is an arithmetic number, because the mean of its divisors is an integer number (2223165).

Almost surely, 2^21340625 is an apocalyptic number.

21340625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21340625 is a deficient number, since it is larger than the sum of its proper divisors (5337355).

21340625 is an frugal number, since it uses more digits than its factorization.

21340625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6854 (or 6834 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21340625 is about 4619.5914321507. The cubic root of 21340625 is about 277.3761046364.

Adding to 21340625 its reverse (52604312), we get a palindrome (73944937).

The spelling of 21340625 in words is "twenty-one million, three hundred forty thousand, six hundred twenty-five".