25780555 has 4 divisors (see below), whose sum is σ = 30936672. Its totient is φ = 20624440.

The previous prime is 25780529. The next prime is 25780567. The reversal of 25780555 is 55508752.

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

It is not a de Polignac number, because 25780555 - 2¹¹ = 25778507 is a prime.

It is a super-2 number, since 2×25780555² = 1329274032216050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2578051 + ... + 2578060.

It is an arithmetic number, because the mean of its divisors is an integer number (7734168).

Almost surely, 2^25780555 is an apocalyptic number.

25780555 is a deficient number, since it is larger than the sum of its proper divisors (5156117).

25780555 is an equidigital number, since it uses as much as digits as its factorization.

25780555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5156116.

The product of its (nonzero) digits is 70000, while the sum is 37.

The square root of 25780555 is about 5077.4555635672. The cubic root of 25780555 is about 295.4137830227.

It can be divided in two parts, 25780 and 555, that added together give a triangular number (26335 = T₂₂₉).

The spelling of 25780555 in words is "twenty-five million, seven hundred eighty thousand, five hundred fifty-five".