201977621 has 2 divisors, whose sum is σ = 201977622. Its totient is φ = 201977620.

The previous prime is 201977609. The next prime is 201977623. The reversal of 201977621 is 126779102.

201977621 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., 197093521 + 4884100 = 14039^2 + 2210^2 .

It is a cyclic number.

It is not a de Polignac number, because 201977621 - 2⁶ = 201977557 is a prime.

It is a Sophie Germain prime.

Together with 201977623, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201977623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100988810 + 100988811.

It is an arithmetic number, because the mean of its divisors is an integer number (100988811).

Almost surely, 2^201977621 is an apocalyptic number.

It is an amenable number.

201977621 is a deficient number, since it is larger than the sum of its proper divisors (1).

201977621 is an equidigital number, since it uses as much as digits as its factorization.

201977621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10584, while the sum is 35.

The square root of 201977621 is about 14211.8830912726. The cubic root of 201977621 is about 586.7247620599.

The spelling of 201977621 in words is "two hundred one million, nine hundred seventy-seven thousand, six hundred twenty-one".