1581788881 has 2 divisors, whose sum is σ = 1581788882. Its totient is φ = 1581788880.

The previous prime is 1581788849. The next prime is 1581788899. The reversal of 1581788881 is 1888871851.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1560250000 + 21538881 = 39500^2 + 4641^2 .

It is a cyclic number.

It is not a de Polignac number, because 1581788881 - 2⁵ = 1581788849 is a prime.

It is a super-2 number, since 2×1581788881² = 5004112128110464322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1581788801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 790894440 + 790894441.

It is an arithmetic number, because the mean of its divisors is an integer number (790894441).

Almost surely, 2^1581788881 is an apocalyptic number.

It is an amenable number.

1581788881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1581788881 is an equidigital number, since it uses as much as digits as its factorization.

1581788881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1146880, while the sum is 55.

The square root of 1581788881 is about 39771.7095559142. The cubic root of 1581788881 is about 1165.1526827463.

The spelling of 1581788881 in words is "one billion, five hundred eighty-one million, seven hundred eighty-eight thousand, eight hundred eighty-one".