1156201221 has 16 divisors (see below), whose sum is σ = 1769399424. Its totient is φ = 657848064.

The previous prime is 1156201219. The next prime is 1156201231. The reversal of 1156201221 is 1221026511.

It is not a de Polignac number, because 1156201221 - 2¹ = 1156201219 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1156201231) 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, 113256 + ... + 123041.

It is an arithmetic number, because the mean of its divisors is an integer number (110587464).

Almost surely, 2^1156201221 is an apocalyptic number.

It is an amenable number.

1156201221 is a deficient number, since it is larger than the sum of its proper divisors (613198203).

1156201221 is a wasteful number, since it uses less digits than its factorization.

1156201221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236540.

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 1156201221 is about 34002.9590035926. The cubic root of 1156201221 is about 1049.5693535578.

Adding to 1156201221 its reverse (1221026511), we get a palindrome (2377227732).

The spelling of 1156201221 in words is "one billion, one hundred fifty-six million, two hundred one thousand, two hundred twenty-one".