201991365 has 48 divisors (see below), whose sum is σ = 375895728. Its totient is φ = 99975168.

The previous prime is 201991357. The next prime is 201991367. The reversal of 201991365 is 563199102.

201991365 is a `hidden beast` number, since 201 + 9 + 91 + 365 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 12047841 + 189943524 = 3471^2 + 13782^2 .

It is not a de Polignac number, because 201991365 - 2³ = 201991357 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201991367) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 54037 + ... + 57653.

It is an arithmetic number, because the mean of its divisors is an integer number (7831161).

Almost surely, 2^201991365 is an apocalyptic number.

It is an amenable number.

201991365 is a deficient number, since it is larger than the sum of its proper divisors (173904363).

201991365 is a wasteful number, since it uses less digits than its factorization.

201991365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3718 (or 3715 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The square root of 201991365 is about 14212.3666220654. The cubic root of 201991365 is about 586.7380700726.

The spelling of 201991365 in words is "two hundred one million, nine hundred ninety-one thousand, three hundred sixty-five".