207213821 has 2 divisors, whose sum is σ = 207213822. Its totient is φ = 207213820.

The previous prime is 207213793. The next prime is 207213869. The reversal of 207213821 is 128312702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 193627225 + 13586596 = 13915^2 + 3686^2 .

It is a cyclic number.

It is not a de Polignac number, because 207213821 - 2⁶ = 207213757 is a prime.

It is a super-2 number, since 2×207213821² = 85875135226840082, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (207213421) by changing a digit.

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 as a sum of consecutive naturals, namely, 103606910 + 103606911.

It is an arithmetic number, because the mean of its divisors is an integer number (103606911).

Almost surely, 2^207213821 is an apocalyptic number.

It is an amenable number.

207213821 is a deficient number, since it is larger than the sum of its proper divisors (1).

207213821 is an equidigital number, since it uses as much as digits as its factorization.

207213821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 207213821 is about 14394.9234454373. The cubic root of 207213821 is about 591.7517801071.

It can be divided in two parts, 20721 and 3821, that added together give a palindrome (24542).

The spelling of 207213821 in words is "two hundred seven million, two hundred thirteen thousand, eight hundred twenty-one".