25440421205429 has 4 divisors (see below), whose sum is σ = 25440432173100. Its totient is φ = 25440410237760.

The previous prime is 25440421205411. The next prime is 25440421205443. The reversal of 25440421205429 is 92450212404452.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 9330593378404 + 16109827827025 = 3054602^2 + 4013705^2 .

It is a cyclic number.

It is not a de Polignac number, because 25440421205429 - 2¹² = 25440421201333 is a prime.

It is a super-2 number, since 2×25440421205429² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 25440421205429.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25440421235429) 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, 486404 + ... + 7149645.

It is an arithmetic number, because the mean of its divisors is an integer number (6360108043275).

Almost surely, 2^{25440421205429} is an apocalyptic number.

It is an amenable number.

25440421205429 is a deficient number, since it is larger than the sum of its proper divisors (10967671).

25440421205429 is an equidigital number, since it uses as much as digits as its factorization.

25440421205429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10967670.

The product of its (nonzero) digits is 921600, while the sum is 44.

The spelling of 25440421205429 in words is "twenty-five trillion, four hundred forty billion, four hundred twenty-one million, two hundred five thousand, four hundred twenty-nine".