21541025 has 18 divisors (see below), whose sum is σ = 29364006. Its totient is φ = 15664000.

The previous prime is 21541021. The next prime is 21541027. The reversal of 21541025 is 52014512.

It can be written as a sum of positive squares in 3 ways, for example, as 94864 + 21446161 = 308^2 + 4631^2 .

It is not a de Polignac number, because 21541025 - 2² = 21541021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21540988 and 21541006.

It is not an unprimeable number, because it can be changed into a prime (21541021) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 536 + ... + 6585.

Almost surely, 2^21541025 is an apocalyptic number.

21541025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21541025 is a deficient number, since it is larger than the sum of its proper divisors (7822981).

21541025 is a wasteful number, since it uses less digits than its factorization.

21541025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7153 (or 7137 counting only the distinct ones).

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

The square root of 21541025 is about 4641.2309789538. The cubic root of 21541025 is about 278.2416381548.

Adding to 21541025 its reverse (52014512), we get a palindrome (73555537).

The spelling of 21541025 in words is "twenty-one million, five hundred forty-one thousand, twenty-five".