1601201809 has 2 divisors, whose sum is σ = 1601201810. Its totient is φ = 1601201808.

The previous prime is 1601201807. The next prime is 1601201873. The reversal of 1601201809 is 9081021061.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1597760784 + 3441025 = 39972^2 + 1855^2 .

It is a cyclic number.

It is not a de Polignac number, because 1601201809 - 2¹ = 1601201807 is a prime.

Together with 1601201807, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1601201807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 800600904 + 800600905.

It is an arithmetic number, because the mean of its divisors is an integer number (800600905).

Almost surely, 2^1601201809 is an apocalyptic number.

It is an amenable number.

1601201809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1601201809 is an equidigital number, since it uses as much as digits as its factorization.

1601201809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 1601201809 is about 40015.0197925729. The cubic root of 1601201809 is about 1169.8998645642.

The spelling of 1601201809 in words is "one billion, six hundred one million, two hundred one thousand, eight hundred nine".