4001212091809 has 3 divisors (see below), whose sum is σ = 4001214092113. Its totient is φ = 4001210091506.

The previous prime is 4001212091801. The next prime is 4001212091813. The reversal of 4001212091809 is 9081902121004.

The square root of 4001212091809 is 2000303.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 4001212091809 - 2³ = 4001212091801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4001212091801) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1000152 + ... + 3000454.

Almost surely, 2^{4001212091809} is an apocalyptic number.

4001212091809 is the 2000303-rd square number.

4001212091809 is the 1000152-nd centered octagonal number.

It is an amenable number.

4001212091809 is a deficient number, since it is larger than the sum of its proper divisors (2000304).

4001212091809 is an frugal number, since it uses more digits than its factorization.

4001212091809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4000606 (or 2000303 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 37.

The spelling of 4001212091809 in words is "four trillion, one billion, two hundred twelve million, ninety-one thousand, eight hundred nine".