21004131025 has 12 divisors (see below), whose sum is σ = 26235237132. Its totient is φ = 16680650240.

The previous prime is 21004131017. The next prime is 21004131041. The reversal of 21004131025 is 52013140012.

It can be written as a sum of positive squares in 6 ways, for example, as 10439361 + 20993691664 = 3231^2 + 144892^2 .

It is not a de Polignac number, because 21004131025 - 2³ = 21004131017 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21004130993 and 21004131011.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3062872 + ... + 3069721.

It is an arithmetic number, because the mean of its divisors is an integer number (2186269761).

Almost surely, 2^21004131025 is an apocalyptic number.

21004131025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21004131025 is a deficient number, since it is larger than the sum of its proper divisors (5231106107).

21004131025 is a wasteful number, since it uses less digits than its factorization.

21004131025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6132740 (or 6132735 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

Adding to 21004131025 its reverse (52013140012), we get a palindrome (73017271037).

The spelling of 21004131025 in words is "twenty-one billion, four million, one hundred thirty-one thousand, twenty-five".