202101821 has 2 divisors, whose sum is σ = 202101822. Its totient is φ = 202101820.

The previous prime is 202101817. The next prime is 202101827. The reversal of 202101821 is 128101202.

It is a happy number.

202101821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 189062500 + 13039321 = 13750^2 + 3611^2 .

It is a cyclic number.

It is not a de Polignac number, because 202101821 - 2² = 202101817 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 202101821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (202101827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 101050910 + 101050911.

It is an arithmetic number, because the mean of its divisors is an integer number (101050911).

Almost surely, 2^202101821 is an apocalyptic number.

It is an amenable number.

202101821 is a deficient number, since it is larger than the sum of its proper divisors (1).

202101821 is an equidigital number, since it uses as much as digits as its factorization.

202101821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 202101821 is about 14216.2520025498. The cubic root of 202101821 is about 586.8450002717.

The spelling of 202101821 in words is "two hundred two million, one hundred one thousand, eight hundred twenty-one".