1155221101 has 4 divisors (see below), whose sum is σ = 1182086752. Its totient is φ = 1128355452.

The previous prime is 1155221099. The next prime is 1155221143. The reversal of 1155221101 is 1011225511.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1155221101 - 2¹ = 1155221099 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 (1155221201) 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, 13432761 + ... + 13432846.

It is an arithmetic number, because the mean of its divisors is an integer number (295521688).

Almost surely, 2^1155221101 is an apocalyptic number.

It is an amenable number.

1155221101 is a deficient number, since it is larger than the sum of its proper divisors (26865651).

1155221101 is an equidigital number, since it uses as much as digits as its factorization.

1155221101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26865650.

The product of its (nonzero) digits is 100, while the sum is 19.

The square root of 1155221101 is about 33988.5436728319. The cubic root of 1155221101 is about 1049.2726939127.

Adding to 1155221101 its reverse (1011225511), we get a palindrome (2166446612).

The spelling of 1155221101 in words is "one billion, one hundred fifty-five million, two hundred twenty-one thousand, one hundred one".