1211309028 has 18 divisors (see below), whose sum is σ = 3061920134. Its totient is φ = 403769664.

The previous prime is 1211309023. The next prime is 1211309039. The reversal of 1211309028 is 8209031121.

It can be written as a sum of positive squares in only one way, i.e., 677144484 + 534164544 = 26022^2 + 23112^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×1211309028² = 2934539122628609568, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1211308992 and 1211309010.

It is not an unprimeable number, because it can be changed into a prime (1211309023) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 16823701 + ... + 16823772.

Almost surely, 2^1211309028 is an apocalyptic number.

1211309028 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1211309028 is an abundant number, since it is smaller than the sum of its proper divisors (1850611106).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211309028 is a wasteful number, since it uses less digits than its factorization.

1211309028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33647483 (or 33647478 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 1211309028 is about 34803.8651301835. The cubic root of 1211309028 is about 1065.9863691208.

The spelling of 1211309028 in words is "one billion, two hundred eleven million, three hundred nine thousand, twenty-eight".