25437211561 has 4 divisors (see below), whose sum is σ = 25868350800. Its totient is φ = 25006072324.

The previous prime is 25437211559. The next prime is 25437211567. The reversal of 25437211561 is 16511273452.

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 25437211561 - 2¹ = 25437211559 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 25437211561.

It is not an unprimeable number, because it can be changed into a prime (25437211567) 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, 215569531 + ... + 215569648.

It is an arithmetic number, because the mean of its divisors is an integer number (6467087700).

Almost surely, 2^25437211561 is an apocalyptic number.

It is an amenable number.

25437211561 is a deficient number, since it is larger than the sum of its proper divisors (431139239).

25437211561 is an equidigital number, since it uses as much as digits as its factorization.

25437211561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431139238.

The product of its digits is 50400, while the sum is 37.

The spelling of 25437211561 in words is "twenty-five billion, four hundred thirty-seven million, two hundred eleven thousand, five hundred sixty-one".