1128267721 has 8 divisors (see below), whose sum is σ = 1304985024. Its totient is φ = 955434480.

The previous prime is 1128267719. The next prime is 1128267743. The reversal of 1128267721 is 1277628211.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1128267721 - 2¹ = 1128267719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1128267121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 970390 + ... + 971551.

It is an arithmetic number, because the mean of its divisors is an integer number (163123128).

Almost surely, 2^1128267721 is an apocalyptic number.

It is an amenable number.

1128267721 is a deficient number, since it is larger than the sum of its proper divisors (176717303).

1128267721 is an equidigital number, since it uses as much as digits as its factorization.

1128267721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1942031.

The product of its digits is 18816, while the sum is 37.

The square root of 1128267721 is about 33589.6966494191. The cubic root of 1128267721 is about 1041.0479208759.

It can be divided in two parts, 11282 and 67721, that added together give a triangular number (79003 = T₃₉₇).

The spelling of 1128267721 in words is "one billion, one hundred twenty-eight million, two hundred sixty-seven thousand, seven hundred twenty-one".