201581979 has 16 divisors (see below), whose sum is σ = 275915904. Its totient is φ = 130838400.

The previous prime is 201581923. The next prime is 201581983. The reversal of 201581979 is 979185102.

201581979 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 201581979 - 2¹⁵ = 201549211 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 201581979.

It is not an unprimeable number, because it can be changed into a prime (201581999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40339 + ... + 45059.

It is an arithmetic number, because the mean of its divisors is an integer number (17244744).

Almost surely, 2^201581979 is an apocalyptic number.

201581979 is a deficient number, since it is larger than the sum of its proper divisors (74333925).

201581979 is a wasteful number, since it uses less digits than its factorization.

201581979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5098.

The product of its (nonzero) digits is 45360, while the sum is 42.

The square root of 201581979 is about 14197.9568600556. The cubic root of 201581979 is about 586.3414115137.

The spelling of 201581979 in words is "two hundred one million, five hundred eighty-one thousand, nine hundred seventy-nine".