1601551601 has 4 divisors (see below), whose sum is σ = 1724747892. Its totient is φ = 1478355312.

The previous prime is 1601551597. The next prime is 1601551603. The reversal of 1601551601 is 1061551061.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1061551061 = 29 ⋅36605209.

It can be written as a sum of positive squares in 2 ways, for example, as 514200976 + 1087350625 = 22676^2 + 32975^2 .

It is a cyclic number.

It is not a de Polignac number, because 1601551601 - 2² = 1601551597 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1601551603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61598126 + ... + 61598151.

It is an arithmetic number, because the mean of its divisors is an integer number (431186973).

Almost surely, 2^1601551601 is an apocalyptic number.

It is an amenable number.

1601551601 is a deficient number, since it is larger than the sum of its proper divisors (123196291).

1601551601 is a wasteful number, since it uses less digits than its factorization.

1601551601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123196290.

The product of its (nonzero) digits is 900, while the sum is 26.

The square root of 1601551601 is about 40019.3903126972. The cubic root of 1601551601 is about 1169.9850488751.

The spelling of 1601551601 in words is "one billion, six hundred one million, five hundred fifty-one thousand, six hundred one".