25193145491 has 4 divisors (see below), whose sum is σ = 25261792032. Its totient is φ = 25124498952.

The previous prime is 25193145463. The next prime is 25193145511. The reversal of 25193145491 is 19454139152.

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 25193145491 - 2¹⁰ = 25193144467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25193145431) 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, 34322720 + ... + 34323453.

It is an arithmetic number, because the mean of its divisors is an integer number (6315448008).

Almost surely, 2^25193145491 is an apocalyptic number.

25193145491 is a deficient number, since it is larger than the sum of its proper divisors (68646541).

25193145491 is an equidigital number, since it uses as much as digits as its factorization.

25193145491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68646540.

The product of its digits is 194400, while the sum is 44.

The spelling of 25193145491 in words is "twenty-five billion, one hundred ninety-three million, one hundred forty-five thousand, four hundred ninety-one".