1581201845 has 12 divisors (see below), whose sum is σ = 1950118884. Its totient is φ = 1230768000.

The previous prime is 1581201823. The next prime is 1581201847. The reversal of 1581201845 is 5481021851.

It can be written as a sum of positive squares in 6 ways, for example, as 2172676 + 1579029169 = 1474^2 + 39737^2 .

It is not a de Polignac number, because 1581201845 - 2⁶ = 1581201781 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1581201847) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 108656 + ... + 122345.

It is an arithmetic number, because the mean of its divisors is an integer number (162509907).

Almost surely, 2^1581201845 is an apocalyptic number.

It is an amenable number.

1581201845 is a deficient number, since it is larger than the sum of its proper divisors (368917039).

1581201845 is an equidigital number, since it uses as much as digits as its factorization.

1581201845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231080 (or 231043 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 35.

The square root of 1581201845 is about 39764.3288010750. The cubic root of 1581201845 is about 1165.0085271408.

The spelling of 1581201845 in words is "one billion, five hundred eighty-one million, two hundred one thousand, eight hundred forty-five".