201531989 has 2 divisors, whose sum is σ = 201531990. Its totient is φ = 201531988.

The previous prime is 201531977. The next prime is 201532027. The reversal of 201531989 is 989135102.

It is an a-pointer prime, because the next prime (201532027) can be obtained adding 201531989 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 200703889 + 828100 = 14167^2 + 910^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201531989 is a prime.

It is a super-2 number, since 2×201531989² = 81230285180592242, which contains 22 as substring.

It is a Sophie Germain 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 (201531929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100765994 + 100765995.

It is an arithmetic number, because the mean of its divisors is an integer number (100765995).

Almost surely, 2^201531989 is an apocalyptic number.

It is an amenable number.

201531989 is a deficient number, since it is larger than the sum of its proper divisors (1).

201531989 is an equidigital number, since it uses as much as digits as its factorization.

201531989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 201531989 is about 14196.1962863297. The cubic root of 201531989 is about 586.2929388765.

The spelling of 201531989 in words is "two hundred one million, five hundred thirty-one thousand, nine hundred eighty-nine".