4391209021 has 8 divisors (see below), whose sum is σ = 4650244344. Its totient is φ = 4132254720.

The previous prime is 4391209001. The next prime is 4391209049. The reversal of 4391209021 is 1209021934.

It can be written as a sum of positive squares in 4 ways, for example, as 1301405625 + 3089803396 = 36075^2 + 55586^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 4391209021 - 2⁷ = 4391208893 is a prime.

It is a super-2 number, since 2×4391209021² = 38565433332223556882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4391209001) 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, 118581 + ... + 151141.

It is an arithmetic number, because the mean of its divisors is an integer number (581280543).

Almost surely, 2^4391209021 is an apocalyptic number.

It is an amenable number.

4391209021 is a deficient number, since it is larger than the sum of its proper divisors (259035323).

4391209021 is a wasteful number, since it uses less digits than its factorization.

4391209021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40511.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 4391209021 is about 66266.1981782568. The cubic root of 4391209021 is about 1637.5505051027.

The spelling of 4391209021 in words is "four billion, three hundred ninety-one million, two hundred nine thousand, twenty-one".