25643947 has 4 divisors (see below), whose sum is σ = 29307376. Its totient is φ = 21980520.

The previous prime is 25643921. The next prime is 25643957. The reversal of 25643947 is 74934652.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25643947 is a prime.

It is a super-2 number, since 2×25643947² = 1315224035477618, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (25643957) 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, 1831704 + ... + 1831717.

It is an arithmetic number, because the mean of its divisors is an integer number (7326844).

Almost surely, 2^25643947 is an apocalyptic number.

25643947 is a deficient number, since it is larger than the sum of its proper divisors (3663429).

25643947 is an equidigital number, since it uses as much as digits as its factorization.

25643947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3663428.

The product of its digits is 181440, while the sum is 40.

The square root of 25643947 is about 5063.9852882883. The cubic root of 25643947 is about 294.8910715327.

The spelling of 25643947 in words is "twenty-five million, six hundred forty-three thousand, nine hundred forty-seven".