1211320091 has 24 divisors (see below), whose sum is σ = 1377816000. Its totient is φ = 1061472384.

The previous prime is 1211320079. The next prime is 1211320147. The reversal of 1211320091 is 1900231121.

It is not a de Polignac number, because 1211320091 - 2⁶ = 1211320027 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1211320291) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 322100 + ... + 325838.

It is an arithmetic number, because the mean of its divisors is an integer number (57409000).

Almost surely, 2^1211320091 is an apocalyptic number.

1211320091 is a deficient number, since it is larger than the sum of its proper divisors (166495909).

1211320091 is a wasteful number, since it uses less digits than its factorization.

1211320091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3851 (or 3834 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 1211320091 is about 34804.0240633177. The cubic root of 1211320091 is about 1065.9896143624.

The spelling of 1211320091 in words is "one billion, two hundred eleven million, three hundred twenty thousand, ninety-one".