21169025 has 12 divisors (see below), whose sum is σ = 26310444. Its totient is φ = 16896000.

The previous prime is 21169009. The next prime is 21169033. The reversal of 21169025 is 52096112.

It can be written as a sum of positive squares in 6 ways, for example, as 2446096 + 18722929 = 1564^2 + 4327^2 .

It is not a de Polignac number, because 21169025 - 2⁴ = 21169009 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21168985 and 21169003.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15365 + ... + 16685.

It is an arithmetic number, because the mean of its divisors is an integer number (2192537).

Almost surely, 2^21169025 is an apocalyptic number.

21169025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21169025 is a deficient number, since it is larger than the sum of its proper divisors (5141419).

21169025 is a wasteful number, since it uses less digits than its factorization.

21169025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1972 (or 1967 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 21169025 is about 4600.9808736833. The cubic root of 21169025 is about 276.6306423959.

It can be divided in two parts, 2116 and 9025, that multiplied together give a square (19096900 = 4370²).

The spelling of 21169025 in words is "twenty-one million, one hundred sixty-nine thousand, twenty-five".