25465509491 has 4 divisors (see below), whose sum is σ = 25469048184. Its totient is φ = 25461970800.

The previous prime is 25465509473. The next prime is 25465509529. The reversal of 25465509491 is 19490556452.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 25465509491 - 2⁶ = 25465509427 is a prime.

It is a super-2 number, since 2×25465509491² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25468509491) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1758530 + ... + 1772951.

It is an arithmetic number, because the mean of its divisors is an integer number (6367262046).

Almost surely, 2^25465509491 is an apocalyptic number.

25465509491 is a deficient number, since it is larger than the sum of its proper divisors (3538693).

25465509491 is an equidigital number, since it uses as much as digits as its factorization.

25465509491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3538692.

The product of its (nonzero) digits is 1944000, while the sum is 50.

The spelling of 25465509491 in words is "twenty-five billion, four hundred sixty-five million, five hundred nine thousand, four hundred ninety-one".