25605021 has 12 divisors (see below), whose sum is σ = 36968928. Its totient is φ = 15756624.

The previous prime is 25605017. The next prime is 25605023. The reversal of 25605021 is 12050652.

It is not a de Polignac number, because 25605021 - 2² = 25605017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25605023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24745 + ... + 25758.

It is an arithmetic number, because the mean of its divisors is an integer number (3080744).

Almost surely, 2^25605021 is an apocalyptic number.

It is an amenable number.

25605021 is a deficient number, since it is larger than the sum of its proper divisors (11363907).

25605021 is a wasteful number, since it uses less digits than its factorization.

25605021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50532 (or 50519 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 25605021 is about 5060.1404130716. The cubic root of 25605021 is about 294.7417868839.

Adding to 25605021 its reverse (12050652), we get a palindrome (37655673).

The spelling of 25605021 in words is "twenty-five million, six hundred five thousand, twenty-one".