25642021 has 4 divisors (see below), whose sum is σ = 26062444. Its totient is φ = 25221600.

The previous prime is 25642013. The next prime is 25642051. The reversal of 25642021 is 12024652.

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 12173121 + 13468900 = 3489^2 + 3670^2 .

It is a cyclic number.

It is not a de Polignac number, because 25642021 - 2³ = 25642013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 25641983 and 25642001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25642051) 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, 210120 + ... + 210241.

It is an arithmetic number, because the mean of its divisors is an integer number (6515611).

Almost surely, 2^25642021 is an apocalyptic number.

It is an amenable number.

25642021 is a deficient number, since it is larger than the sum of its proper divisors (420423).

25642021 is an equidigital number, since it uses as much as digits as its factorization.

25642021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 420422.

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 25642021 is about 5063.7951182883. The cubic root of 25642021 is about 294.8836887064.

Adding to 25642021 its reverse (12024652), we get a palindrome (37666673).

The spelling of 25642021 in words is "twenty-five million, six hundred forty-two thousand, twenty-one".