21004104025 has 6 divisors (see below), whose sum is σ = 26045089022. Its totient is φ = 16803283200.

The previous prime is 21004104013. The next prime is 21004104029. The reversal of 21004104025 is 52040140012.

It can be written as a sum of positive squares in 3 ways, for example, as 7167992896 + 13836111129 = 84664^2 + 117627^2 .

It is not a de Polignac number, because 21004104025 - 2²³ = 20995715417 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21004103993 and 21004104011.

It is not an unprimeable number, because it can be changed into a prime (21004104029) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 420082056 + ... + 420082105.

Almost surely, 2^21004104025 is an apocalyptic number.

21004104025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21004104025 is a deficient number, since it is larger than the sum of its proper divisors (5040984997).

21004104025 is an equidigital number, since it uses as much as digits as its factorization.

21004104025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840164171 (or 840164166 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

Adding to 21004104025 its reverse (52040140012), we get a palindrome (73044244037).

The spelling of 21004104025 in words is "twenty-one billion, four million, one hundred four thousand, twenty-five".