1155215021 has 4 divisors (see below), whose sum is σ = 1179794112. Its totient is φ = 1130635932.

The previous prime is 1155214993. The next prime is 1155215041. The reversal of 1155215021 is 1205125511.

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 1155215021 - 2²⁶ = 1088106157 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 (1155215041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12289475 + ... + 12289568.

It is an arithmetic number, because the mean of its divisors is an integer number (294948528).

Almost surely, 2^1155215021 is an apocalyptic number.

It is an amenable number.

1155215021 is a deficient number, since it is larger than the sum of its proper divisors (24579091).

1155215021 is an equidigital number, since it uses as much as digits as its factorization.

1155215021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24579090.

The product of its (nonzero) digits is 500, while the sum is 23.

The square root of 1155215021 is about 33988.4542308120. The cubic root of 1155215021 is about 1049.2708531138.

The spelling of 1155215021 in words is "one billion, one hundred fifty-five million, two hundred fifteen thousand, twenty-one".