201921109 has 4 divisors (see below), whose sum is σ = 217453516. Its totient is φ = 186388704.

The previous prime is 201921107. The next prime is 201921131. The reversal of 201921109 is 901129102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 104346225 + 97574884 = 10215^2 + 9878^2 .

It is a cyclic number.

It is not a de Polignac number, because 201921109 - 2¹ = 201921107 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201921107) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7766184 + ... + 7766209.

It is an arithmetic number, because the mean of its divisors is an integer number (54363379).

Almost surely, 2^201921109 is an apocalyptic number.

It is an amenable number.

201921109 is a deficient number, since it is larger than the sum of its proper divisors (15532407).

201921109 is a wasteful number, since it uses less digits than its factorization.

201921109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15532406.

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 201921109 is about 14209.8947568235. The cubic root of 201921109 is about 586.6700363888.

The spelling of 201921109 in words is "two hundred one million, nine hundred twenty-one thousand, one hundred nine".