25923786781 has 4 divisors (see below), whose sum is σ = 25925246812. Its totient is φ = 25922326752.

The previous prime is 25923786743. The next prime is 25923786793. The reversal of 25923786781 is 18768732952.

It is a happy number.

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 16546963225 + 9376823556 = 128635^2 + 96834^2 .

It is a cyclic number.

It is not a de Polignac number, because 25923786781 - 2¹³ = 25923778589 is a prime.

It is a super-2 number, since 2×25923786781² (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 (25923586781) 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, 703050 + ... + 739003.

It is an arithmetic number, because the mean of its divisors is an integer number (6481311703).

Almost surely, 2^25923786781 is an apocalyptic number.

It is an amenable number.

25923786781 is a deficient number, since it is larger than the sum of its proper divisors (1460031).

25923786781 is a wasteful number, since it uses less digits than its factorization.

25923786781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1460030.

The product of its digits is 10160640, while the sum is 58.

The spelling of 25923786781 in words is "twenty-five billion, nine hundred twenty-three million, seven hundred eighty-six thousand, seven hundred eighty-one".