21058825 has 6 divisors (see below), whose sum is σ = 26112974. Its totient is φ = 16847040.

The previous prime is 21058819. The next prime is 21058853. The reversal of 21058825 is 52885012.

It can be written as a sum of positive squares in 3 ways, for example, as 5400976 + 15657849 = 2324^2 + 3957^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21058825 is a prime.

It is a super-2 number, since 2×21058825² = 886948220761250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

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, 421152 + ... + 421201.

Almost surely, 2^21058825 is an apocalyptic number.

21058825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21058825 is a deficient number, since it is larger than the sum of its proper divisors (5054149).

21058825 is an equidigital number, since it uses as much as digits as its factorization.

21058825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 842363 (or 842358 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 31.

The square root of 21058825 is about 4588.9895401929. The cubic root of 21058825 is about 276.1497865453.

The spelling of 21058825 in words is "twenty-one million, fifty-eight thousand, eight hundred twenty-five".