21183785825 has 12 divisors (see below), whose sum is σ = 26270624748. Its totient is φ = 16945267200.

The previous prime is 21183785813. The next prime is 21183785863. The reversal of 21183785825 is 52858738112.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 1846936576 + 19336849249 = 42976^2 + 139057^2 .

It is not a de Polignac number, because 21183785825 - 2¹⁰ = 21183784801 is a prime.

It is a hoax number, since the sum of its digits (50) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a Curzon 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, 236285 + ... + 313365.

It is an arithmetic number, because the mean of its divisors is an integer number (2189218729).

Almost surely, 2^21183785825 is an apocalyptic number.

21183785825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21183785825 is a deficient number, since it is larger than the sum of its proper divisors (5086838923).

21183785825 is a wasteful number, since it uses less digits than its factorization.

21183785825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88084 (or 88079 counting only the distinct ones).

The product of its digits is 1075200, while the sum is 50.

The spelling of 21183785825 in words is "twenty-one billion, one hundred eighty-three million, seven hundred eighty-five thousand, eight hundred twenty-five".