25821012 has 48 divisors (see below), whose sum is σ = 69587840. Its totient is φ = 7299072.

The previous prime is 25820989. The next prime is 25821043. The reversal of 25821012 is 21012852.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 25821012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6564 + ... + 9732.

Almost surely, 2^25821012 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25821012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34793920).

25821012 is an abundant number, since it is smaller than the sum of its proper divisors (43766828).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25821012 is a wasteful number, since it uses less digits than its factorization.

25821012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3280 (or 3278 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 25821012 is about 5081.4379854525. The cubic root of 25821012 is about 295.5682315864.

Adding to 25821012 its reverse (21012852), we get a palindrome (46833864).

The spelling of 25821012 in words is "twenty-five million, eight hundred twenty-one thousand, twelve".