1209009021 has 32 divisors (see below), whose sum is σ = 1819238400. Its totient is φ = 707553600.

The previous prime is 1209009017. The next prime is 1209009041.

1209009021 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1209009021 - 2² = 1209009017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1209008982 and 1209009000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1209009001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 611791 + ... + 613763.

It is an arithmetic number, because the mean of its divisors is an integer number (56851200).

Almost surely, 2^1209009021 is an apocalyptic number.

1209009021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1209009021 is a deficient number, since it is larger than the sum of its proper divisors (610229379).

1209009021 is a wasteful number, since it uses less digits than its factorization.

1209009021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2617.

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 1209009021 is about 34770.8070225584. The cubic root of 1209009021 is about 1065.3112511324.

It can be divided in two parts, 120900 and 9021, that added together give a palindrome (129921).

The spelling of 1209009021 in words is "one billion, two hundred nine million, nine thousand, twenty-one".