25661224009 has 4 divisors (see below), whose sum is σ = 25663945216. Its totient is φ = 25658502804.

The previous prime is 25661223979. The next prime is 25661224049. The reversal of 25661224009 is 90042216652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 25661224009 - 2²⁹ = 25124353097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25661224049) 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, 1346409 + ... + 1365334.

It is an arithmetic number, because the mean of its divisors is an integer number (6415986304).

Almost surely, 2^25661224009 is an apocalyptic number.

It is an amenable number.

25661224009 is a deficient number, since it is larger than the sum of its proper divisors (2721207).

25661224009 is an equidigital number, since it uses as much as digits as its factorization.

25661224009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2721206.

The product of its (nonzero) digits is 51840, while the sum is 37.

The spelling of 25661224009 in words is "twenty-five billion, six hundred sixty-one million, two hundred twenty-four thousand, nine".