21025834 has 4 divisors (see below), whose sum is σ = 31538754. Its totient is φ = 10512916.

The previous prime is 21025831. The next prime is 21025861. The reversal of 21025834 is 43852012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 11122225 + 9903609 = 3335^2 + 3147^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21025799 and 21025808.

It is not an unprimeable number, because it can be changed into a prime (21025831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5256457 + ... + 5256460.

Almost surely, 2^21025834 is an apocalyptic number.

21025834 is a deficient number, since it is larger than the sum of its proper divisors (10512920).

21025834 is a wasteful number, since it uses less digits than its factorization.

21025834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10512919.

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

The square root of 21025834 is about 4585.3935490861. The cubic root of 21025834 is about 276.0055046861.

Adding to 21025834 its reverse (43852012), we get a palindrome (64877846).

The spelling of 21025834 in words is "twenty-one million, twenty-five thousand, eight hundred thirty-four".