212821925 has 6 divisors (see below), whose sum is σ = 263899218. Its totient is φ = 170257520.

The previous prime is 212821919. The next prime is 212821933. The reversal of 212821925 is 529128212.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 51811204 + 161010721 = 7198^2 + 12689^2 .

It is not a de Polignac number, because 212821925 - 2¹⁰ = 212820901 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 212821891 and 212821900.

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 5 ways as a sum of consecutive naturals, for example, 4256414 + ... + 4256463.

It is an arithmetic number, because the mean of its divisors is an integer number (43983203).

Almost surely, 2^212821925 is an apocalyptic number.

212821925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

212821925 is a deficient number, since it is larger than the sum of its proper divisors (51077293).

212821925 is an equidigital number, since it uses as much as digits as its factorization.

212821925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8512887 (or 8512882 counting only the distinct ones).

The product of its digits is 5760, while the sum is 32.

The square root of 212821925 is about 14588.4174947113. The cubic root of 212821925 is about 597.0427867246.

The spelling of 212821925 in words is "two hundred twelve million, eight hundred twenty-one thousand, nine hundred twenty-five".