202991021 has 2 divisors, whose sum is σ = 202991022. Its totient is φ = 202991020.

The previous prime is 202990993. The next prime is 202991023. The reversal of 202991021 is 120199202.

It is a happy number.

202991021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 179854921 + 23136100 = 13411^2 + 4810^2 .

It is a cyclic number.

It is not a de Polignac number, because 202991021 - 2²⁶ = 135882157 is a prime.

Together with 202991023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (202991023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 101495510 + 101495511.

It is an arithmetic number, because the mean of its divisors is an integer number (101495511).

Almost surely, 2^202991021 is an apocalyptic number.

It is an amenable number.

202991021 is a deficient number, since it is larger than the sum of its proper divisors (1).

202991021 is an equidigital number, since it uses as much as digits as its factorization.

202991021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 202991021 is about 14247.4917441633. The cubic root of 202991021 is about 587.7044006445.

The spelling of 202991021 in words is "two hundred two million, nine hundred ninety-one thousand, twenty-one".