25661734542 has 24 divisors (see below), whose sum is σ = 57517682040. Its totient is φ = 8258948880.

The previous prime is 25661734537. The next prime is 25661734561. The reversal of 25661734542 is 24543716652.

25661734542 is a `hidden beast` number, since 2 + 5 + 66 + 17 + 34 + 542 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24579684 + ... + 24580727.

It is an arithmetic number, because the mean of its divisors is an integer number (2396570085).

Almost surely, 2^25661734542 is an apocalyptic number.

25661734542 is an abundant number, since it is smaller than the sum of its proper divisors (31855947498).

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

25661734542 is a wasteful number, since it uses less digits than its factorization.

25661734542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49160448 (or 49160445 counting only the distinct ones).

The product of its digits is 1209600, while the sum is 45.

The spelling of 25661734542 in words is "twenty-five billion, six hundred sixty-one million, seven hundred thirty-four thousand, five hundred forty-two".