21203105525 has 12 divisors (see below), whose sum is σ = 30047829792. Its totient is φ = 14539272240.

The previous prime is 21203105513. The next prime is 21203105533. The reversal of 21203105525 is 52550130212.

It is not a de Polignac number, because 21203105525 - 2⁴ = 21203105509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21203105494 and 21203105503.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60580127 + ... + 60580476.

It is an arithmetic number, because the mean of its divisors is an integer number (2503985816).

Almost surely, 2^21203105525 is an apocalyptic number.

21203105525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21203105525 is a deficient number, since it is larger than the sum of its proper divisors (8844724267).

21203105525 is a wasteful number, since it uses less digits than its factorization.

21203105525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121160620 (or 121160615 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 26.

Adding to 21203105525 its reverse (52550130212), we get a palindrome (73753235737).

The spelling of 21203105525 in words is "twenty-one billion, two hundred three million, one hundred five thousand, five hundred twenty-five".