25779582821 has 4 divisors (see below), whose sum is σ = 26900434272. Its totient is φ = 24658731372.

The previous prime is 25779582817. The next prime is 25779582823. The reversal of 25779582821 is 12828597752.

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 25779582821 - 2² = 25779582817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25779582823) 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, 560425691 + ... + 560425736.

It is an arithmetic number, because the mean of its divisors is an integer number (6725108568).

Almost surely, 2^25779582821 is an apocalyptic number.

It is an amenable number.

25779582821 is a deficient number, since it is larger than the sum of its proper divisors (1120851451).

25779582821 is a wasteful number, since it uses less digits than its factorization.

25779582821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1120851450.

The product of its digits is 5644800, while the sum is 56.

The spelling of 25779582821 in words is "twenty-five billion, seven hundred seventy-nine million, five hundred eighty-two thousand, eight hundred twenty-one".