11201581 has 2 divisors, whose sum is σ = 11201582. Its totient is φ = 11201580.

The previous prime is 11201573. The next prime is 11201587. The reversal of 11201581 is 18510211.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7241481 + 3960100 = 2691^2 + 1990^2 .

It is a cyclic number.

It is not a de Polignac number, because 11201581 - 2³ = 11201573 is a prime.

It is a super-2 number, since 2×11201581² = 250950833799122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11201587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5600790 + 5600791.

It is an arithmetic number, because the mean of its divisors is an integer number (5600791).

Almost surely, 2^11201581 is an apocalyptic number.

It is an amenable number.

11201581 is a deficient number, since it is larger than the sum of its proper divisors (1).

11201581 is an equidigital number, since it uses as much as digits as its factorization.

11201581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 80, while the sum is 19.

The square root of 11201581 is about 3346.8763048550. The cubic root of 11201581 is about 223.7483155830.

Adding to 11201581 its reverse (18510211), we get a palindrome (29711792).

It can be divided in two parts, 1120 and 1581, that added together give a triangular number (2701 = T₇₃).

The spelling of 11201581 in words is "eleven million, two hundred one thousand, five hundred eighty-one".