21415025 has 12 divisors (see below), whose sum is σ = 26737500. Its totient is φ = 17014080.

The previous prime is 21414983. The next prime is 21415027. The reversal of 21415025 is 52051412.

It can be written as a sum of positive squares in 6 ways, for example, as 8620096 + 12794929 = 2936^2 + 3577^2 .

It is not a de Polignac number, because 21415025 - 2⁶ = 21414961 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21414988 and 21415006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21415027) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 851 + ... + 6599.

It is an arithmetic number, because the mean of its divisors is an integer number (2228125).

Almost surely, 2^21415025 is an apocalyptic number.

21415025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21415025 is a deficient number, since it is larger than the sum of its proper divisors (5322475).

21415025 is a wasteful number, since it uses less digits than its factorization.

21415025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5908 (or 5903 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 21415025 is about 4627.6370860300. The cubic root of 21415025 is about 277.6980703156.

Adding to 21415025 its reverse (52051412), we get a palindrome (73466437).

The spelling of 21415025 in words is "twenty-one million, four hundred fifteen thousand, twenty-five".