4001388120409 has 9 divisors (see below), whose sum is σ = 4007500496863. Its totient is φ = 3995285061712.

The previous prime is 4001388120349. The next prime is 4001388120437. The reversal of 4001388120409 is 9040218831004.

The square root of 4001388120409 is 2000347.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1666384083225 + 2335004037184 = 1290885^2 + 1528072^2 .

It is not a de Polignac number, because 4001388120409 - 2¹¹ = 4001388118361 is a prime.

It is a super-2 number, since 2×4001388120409² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4001388127409) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1906329642 + ... + 1906331740.

Almost surely, 2^{4001388120409} is an apocalyptic number.

4001388120409 is the 2000347-th square number.

4001388120409 is the 1000174-th centered octagonal number.

It is an amenable number.

4001388120409 is a deficient number, since it is larger than the sum of its proper divisors (6112376454).

4001388120409 is an frugal number, since it uses more digits than its factorization.

4001388120409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6104 (or 3052 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 40.

The spelling of 4001388120409 in words is "four trillion, one billion, three hundred eighty-eight million, one hundred twenty thousand, four hundred nine".