201809890 has 16 divisors (see below), whose sum is σ = 384626232. Its totient is φ = 75975424.

The previous prime is 201809851. The next prime is 201809891. The reversal of 201809890 is 98908102.

It can be written as a sum of positive squares in 4 ways, for example, as 160503561 + 41306329 = 12669^2 + 6427^2 .

It is not an unprimeable number, because it can be changed into a prime (201809891) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 593389 + ... + 593728.

Almost surely, 2^201809890 is an apocalyptic number.

201809890 is a deficient number, since it is larger than the sum of its proper divisors (182816342).

201809890 is a wasteful number, since it uses less digits than its factorization.

201809890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1187141.

The product of its (nonzero) digits is 10368, while the sum is 37.

The square root of 201809890 is about 14205.9807827548. The cubic root of 201809890 is about 586.5623031614.

The spelling of 201809890 in words is "two hundred one million, eight hundred nine thousand, eight hundred ninety".