21134825 has 18 divisors (see below), whose sum is σ = 27873774. Its totient is φ = 15841920.

The previous prime is 21134809. The next prime is 21134837. The reversal of 21134825 is 52843112.

It can be written as a sum of positive squares in 3 ways, for example, as 3182656 + 17952169 = 1784^2 + 4237^2 .

It is not a de Polignac number, because 21134825 - 2⁴ = 21134809 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21134794 and 21134803.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 94664 + ... + 94886.

It is an arithmetic number, because the mean of its divisors is an integer number (1548543).

Almost surely, 2^21134825 is an apocalyptic number.

21134825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21134825 is a deficient number, since it is larger than the sum of its proper divisors (6738949).

21134825 is an equidigital number, since it uses as much as digits as its factorization.

21134825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 473 (or 245 counting only the distinct ones).

The product of its digits is 1920, while the sum is 26.

The square root of 21134825 is about 4597.2627725637. The cubic root of 21134825 is about 276.4815902252.

Adding to 21134825 its reverse (52843112), we get a palindrome (73977937).

The spelling of 21134825 in words is "twenty-one million, one hundred thirty-four thousand, eight hundred twenty-five".