201891985 has 4 divisors (see below), whose sum is σ = 242270388. Its totient is φ = 161513584.

The previous prime is 201891959. The next prime is 201892049. The reversal of 201891985 is 589198102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 589198102 = 2 ⋅294599051.

It can be written as a sum of positive squares in 2 ways, for example, as 22439169 + 179452816 = 4737^2 + 13396^2 .

It is a cyclic number.

It is not a de Polignac number, because 201891985 - 2¹¹ = 201889937 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20189194 + ... + 20189203.

It is an arithmetic number, because the mean of its divisors is an integer number (60567597).

Almost surely, 2^201891985 is an apocalyptic number.

It is an amenable number.

201891985 is a deficient number, since it is larger than the sum of its proper divisors (40378403).

201891985 is an equidigital number, since it uses as much as digits as its factorization.

201891985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40378402.

The product of its (nonzero) digits is 51840, while the sum is 43.

The square root of 201891985 is about 14208.8699409911. The cubic root of 201891985 is about 586.6418290033.

The spelling of 201891985 in words is "two hundred one million, eight hundred ninety-one thousand, nine hundred eighty-five".