1213921121 has 16 divisors (see below), whose sum is σ = 1449411840. Its totient is φ = 994660800.

The previous prime is 1213921087. The next prime is 1213921127. The reversal of 1213921121 is 1211293121.

It is not a de Polignac number, because 1213921121 - 2²⁶ = 1146812257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1213921127) 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, 9101 + ... + 50106.

It is an arithmetic number, because the mean of its divisors is an integer number (90588240).

Almost surely, 2^1213921121 is an apocalyptic number.

It is an amenable number.

1213921121 is a deficient number, since it is larger than the sum of its proper divisors (235490719).

1213921121 is a wasteful number, since it uses less digits than its factorization.

1213921121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59344.

The product of its digits is 216, while the sum is 23.

The square root of 1213921121 is about 34841.3708255000. The cubic root of 1213921121 is about 1066.7520576930.

The spelling of 1213921121 in words is "one billion, two hundred thirteen million, nine hundred twenty-one thousand, one hundred twenty-one".