21036425 has 6 divisors (see below), whose sum is σ = 26085198. Its totient is φ = 16829120.

The previous prime is 21036413. The next prime is 21036443. The reversal of 21036425 is 52463012.

It can be written as a sum of positive squares in 3 ways, for example, as 6512704 + 14523721 = 2552^2 + 3811^2 .

It is not a de Polignac number, because 21036425 - 2⁴ = 21036409 is a prime.

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 21036425.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 420704 + ... + 420753.

It is an arithmetic number, because the mean of its divisors is an integer number (4347533).

Almost surely, 2^21036425 is an apocalyptic number.

21036425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21036425 is a deficient number, since it is larger than the sum of its proper divisors (5048773).

21036425 is an equidigital number, since it uses as much as digits as its factorization.

21036425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 841467 (or 841462 counting only the distinct ones).

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

The square root of 21036425 is about 4586.5482663982. The cubic root of 21036425 is about 276.0518394890.

Adding to 21036425 its reverse (52463012), we get a palindrome (73499437).

The spelling of 21036425 in words is "twenty-one million, thirty-six thousand, four hundred twenty-five".