1581643057 has 4 divisors (see below), whose sum is σ = 1583700580. Its totient is φ = 1579585536.

The previous prime is 1581643051. The next prime is 1581643067. The reversal of 1581643057 is 7503461851.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 629056561 + 952586496 = 25081^2 + 30864^2 .

It is a cyclic number.

It is not a de Polignac number, because 1581643057 - 2¹⁹ = 1581118769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1581643051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1027608 + ... + 1029145.

It is an arithmetic number, because the mean of its divisors is an integer number (395925145).

Almost surely, 2^1581643057 is an apocalyptic number.

It is an amenable number.

1581643057 is a deficient number, since it is larger than the sum of its proper divisors (2057523).

1581643057 is an equidigital number, since it uses as much as digits as its factorization.

1581643057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2057522.

The product of its (nonzero) digits is 100800, while the sum is 40.

The square root of 1581643057 is about 39769.8762507504. The cubic root of 1581643057 is about 1165.1168767782.

The spelling of 1581643057 in words is "one billion, five hundred eighty-one million, six hundred forty-three thousand, fifty-seven".