1090198021 has 6 divisors (see below), whose sum is σ = 1198316966. Its totient is φ = 991089000.

The previous prime is 1090198019. The next prime is 1090198037. The reversal of 1090198021 is 1208910901.

It can be written as a sum of positive squares in only one way, i.e., 1035230625 + 54967396 = 32175^2 + 7414^2 .

It is not a de Polignac number, because 1090198021 - 2¹ = 1090198019 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1090198001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4504830 + ... + 4505071.

Almost surely, 2^1090198021 is an apocalyptic number.

1090198021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1090198021 is a deficient number, since it is larger than the sum of its proper divisors (108118945).

1090198021 is an equidigital number, since it uses as much as digits as its factorization.

1090198021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9009923 (or 9009912 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 1090198021 is about 33018.1468438191. The cubic root of 1090198021 is about 1029.2047844555.

The spelling of 1090198021 in words is "one billion, ninety million, one hundred ninety-eight thousand, twenty-one".