25418021 has 4 divisors (see below), whose sum is σ = 25603692. Its totient is φ = 25232352.

The previous prime is 25417993. The next prime is 25418033. The reversal of 25418021 is 12081452.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7022500 + 18395521 = 2650^2 + 4289^2 .

It is a cyclic number.

It is not a de Polignac number, because 25418021 - 2¹⁰ = 25416997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25418051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92630 + ... + 92903.

It is an arithmetic number, because the mean of its divisors is an integer number (6400923).

Almost surely, 2^25418021 is an apocalyptic number.

It is an amenable number.

25418021 is a deficient number, since it is larger than the sum of its proper divisors (185671).

25418021 is a wasteful number, since it uses less digits than its factorization.

25418021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185670.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 25418021 is about 5041.6288042655. The cubic root of 25418021 is about 294.0225081878.

Adding to 25418021 its reverse (12081452), we get a palindrome (37499473).

The spelling of 25418021 in words is "twenty-five million, four hundred eighteen thousand, twenty-one".