25531156205 has 4 divisors (see below), whose sum is σ = 30637387452. Its totient is φ = 20424924960.

The previous prime is 25531156201. The next prime is 25531156243. The reversal of 25531156205 is 50265113552.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8713475716 + 16817680489 = 93346^2 + 129683^2 .

It is not a de Polignac number, because 25531156205 - 2² = 25531156201 is a prime.

It is a super-2 number, since 2×25531156205² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25531156201) 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, 2553115616 + ... + 2553115625.

It is an arithmetic number, because the mean of its divisors is an integer number (7659346863).

Almost surely, 2^25531156205 is an apocalyptic number.

It is an amenable number.

25531156205 is a deficient number, since it is larger than the sum of its proper divisors (5106231247).

25531156205 is an equidigital number, since it uses as much as digits as its factorization.

25531156205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5106231246.

The product of its (nonzero) digits is 45000, while the sum is 35.

Adding to 25531156205 its reverse (50265113552), we get a palindrome (75796269757).

The spelling of 25531156205 in words is "twenty-five billion, five hundred thirty-one million, one hundred fifty-six thousand, two hundred five".