25820421 has 16 divisors (see below), whose sum is σ = 39191040. Its totient is φ = 14967920.

The previous prime is 25820419. The next prime is 25820429. The reversal of 25820421 is 12402852.

It is not a de Polignac number, because 25820421 - 2¹ = 25820419 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 25820391 and 25820400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25820429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16251 + ... + 17768.

It is an arithmetic number, because the mean of its divisors is an integer number (2449440).

Almost surely, 2^25820421 is an apocalyptic number.

It is an amenable number.

25820421 is a deficient number, since it is larger than the sum of its proper divisors (13370619).

25820421 is a wasteful number, since it uses less digits than its factorization.

25820421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34056.

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 25820421 is about 5081.3798322897. The cubic root of 25820421 is about 295.5659765475.

Subtracting from 25820421 its reverse (12402852), we obtain a square (13417569 = 3663²).

The spelling of 25820421 in words is "twenty-five million, eight hundred twenty thousand, four hundred twenty-one".