21003543125 has 10 divisors (see below), whose sum is σ = 26246028270. Its totient is φ = 16802834000.

The previous prime is 21003543109. The next prime is 21003543149. The reversal of 21003543125 is 52134530012.

It is a happy number.

It can be written as a sum of positive squares in 5 ways, for example, as 3356811844 + 17646731281 = 57938^2 + 132841^2 .

It is not a de Polignac number, because 21003543125 - 2⁴ = 21003543109 is a prime.

It is a super-2 number, since 2×21003543125² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21003543094 and 21003543103.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 16802210 + ... + 16803459.

It is an arithmetic number, because the mean of its divisors is an integer number (2624602827).

Almost surely, 2^21003543125 is an apocalyptic number.

21003543125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21003543125 is a deficient number, since it is larger than the sum of its proper divisors (5242485145).

21003543125 is an frugal number, since it uses more digits than its factorization.

21003543125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33605689 (or 33605674 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The spelling of 21003543125 in words is "twenty-one billion, three million, five hundred forty-three thousand, one hundred twenty-five".