25121505666 has 32 divisors (see below), whose sum is σ = 51446767680. Its totient is φ = 8173476864.

The previous prime is 25121505583. The next prime is 25121505667. The reversal of 25121505666 is 66650512152.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (25121505667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 351466 + ... + 416858.

It is an arithmetic number, because the mean of its divisors is an integer number (1607711490).

Almost surely, 2^25121505666 is an apocalyptic number.

25121505666 is an abundant number, since it is smaller than the sum of its proper divisors (26325262014).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25121505666 is a wasteful number, since it uses less digits than its factorization.

25121505666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66930.

The product of its (nonzero) digits is 108000, while the sum is 39.

The spelling of 25121505666 in words is "twenty-five billion, one hundred twenty-one million, five hundred five thousand, six hundred sixty-six".