21340825 has 24 divisors (see below), whose sum is σ = 29301696. Its totient is φ = 15288000.

The previous prime is 21340811. The next prime is 21340859. The reversal of 21340825 is 52804312.

It is not a de Polignac number, because 21340825 - 2⁹ = 21340313 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21340825.

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 23 ways as a sum of consecutive naturals, for example, 18979 + ... + 20071.

It is an arithmetic number, because the mean of its divisors is an integer number (1220904).

Almost surely, 2^21340825 is an apocalyptic number.

21340825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21340825 is a deficient number, since it is larger than the sum of its proper divisors (7960871).

21340825 is a wasteful number, since it uses less digits than its factorization.

21340825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1185 (or 1180 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 21340825 is about 4619.6130790359. The cubic root of 21340825 is about 277.3769711379.

The spelling of 21340825 in words is "twenty-one million, three hundred forty thousand, eight hundred twenty-five".