201801997 has 2 divisors, whose sum is σ = 201801998. Its totient is φ = 201801996.

The previous prime is 201801989. The next prime is 201802009. The reversal of 201801997 is 799108102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138980521 + 62821476 = 11789^2 + 7926^2 .

It is a cyclic number.

It is not a de Polignac number, because 201801997 - 2³ = 201801989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201801937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100900998 + 100900999.

It is an arithmetic number, because the mean of its divisors is an integer number (100900999).

Almost surely, 2^201801997 is an apocalyptic number.

It is an amenable number.

201801997 is a deficient number, since it is larger than the sum of its proper divisors (1).

201801997 is an equidigital number, since it uses as much as digits as its factorization.

201801997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 201801997 is about 14205.7029745099. The cubic root of 201801997 is about 586.5546560360.

The spelling of 201801997 in words is "two hundred one million, eight hundred one thousand, nine hundred ninety-seven".