25161111561 has 4 divisors (see below), whose sum is σ = 33548148752. Its totient is φ = 16774074372.

The previous prime is 25161111559. The next prime is 25161111571. The reversal of 25161111561 is 16511116152.

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 not a de Polignac number, because 25161111561 - 2¹ = 25161111559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25161111541) 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, 4193518591 + ... + 4193518596.

It is an arithmetic number, because the mean of its divisors is an integer number (8387037188).

Almost surely, 2^25161111561 is an apocalyptic number.

It is an amenable number.

25161111561 is a deficient number, since it is larger than the sum of its proper divisors (8387037191).

25161111561 is an equidigital number, since it uses as much as digits as its factorization.

25161111561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8387037190.

The product of its digits is 1800, while the sum is 30.

The spelling of 25161111561 in words is "twenty-five billion, one hundred sixty-one million, one hundred eleven thousand, five hundred sixty-one".