21038525 has 6 divisors (see below), whose sum is σ = 26087802. Its totient is φ = 16830800.

The previous prime is 21038519. The next prime is 21038531. The reversal of 21038525 is 52583012.

It is an interprime number because it is at equal distance from previous prime (21038519) and next prime (21038531).

It can be written as a sum of positive squares in 3 ways, for example, as 1493284 + 19545241 = 1222^2 + 4421^2 .

It is not a de Polignac number, because 21038525 - 2¹⁶ = 20972989 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21038494 and 21038503.

It is a congruent number.

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 5 ways as a sum of consecutive naturals, for example, 420746 + ... + 420795.

It is an arithmetic number, because the mean of its divisors is an integer number (4347967).

Almost surely, 2^21038525 is an apocalyptic number.

21038525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21038525 is a deficient number, since it is larger than the sum of its proper divisors (5049277).

21038525 is an equidigital number, since it uses as much as digits as its factorization.

21038525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 841551 (or 841546 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 21038525 is about 4586.7771910133. Note that the first 3 decimals coincide. The cubic root of 21038525 is about 276.0610249784.

The spelling of 21038525 in words is "twenty-one million, thirty-eight thousand, five hundred twenty-five".