25640242 has 4 divisors (see below), whose sum is σ = 38460366. Its totient is φ = 12820120.

The previous prime is 25640227. The next prime is 25640249. The reversal of 25640242 is 24204652.

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

It can be written as a sum of positive squares in only one way, i.e., 13256881 + 12383361 = 3641^2 + 3519^2 .

It is not an unprimeable number, because it can be changed into a prime (25640249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6410059 + ... + 6410062.

Almost surely, 2^25640242 is an apocalyptic number.

25640242 is a deficient number, since it is larger than the sum of its proper divisors (12820124).

25640242 is a wasteful number, since it uses less digits than its factorization.

25640242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12820123.

The product of its (nonzero) digits is 3840, while the sum is 25.

The square root of 25640242 is about 5063.6194564758. The cubic root of 25640242 is about 294.8768690383.

Adding to 25640242 its reverse (24204652), we get a palindrome (49844894).

The spelling of 25640242 in words is "twenty-five million, six hundred forty thousand, two hundred forty-two".