1581673643 has 6 divisors (see below), whose sum is σ = 1738533972. Its totient is φ = 1437885020.

The previous prime is 1581673609. The next prime is 1581673651. The reversal of 1581673643 is 3463761851.

It is not a de Polignac number, because 1581673643 - 2⁶ = 1581673579 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1581673594 and 1581673603.

It is not an unprimeable number, because it can be changed into a prime (1581673663) 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 5 ways as a sum of consecutive naturals, for example, 6535721 + ... + 6535962.

It is an arithmetic number, because the mean of its divisors is an integer number (289755662).

Almost surely, 2^1581673643 is an apocalyptic number.

1581673643 is a deficient number, since it is larger than the sum of its proper divisors (156860329).

1581673643 is a wasteful number, since it uses less digits than its factorization.

1581673643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13071705 (or 13071694 counting only the distinct ones).

The product of its digits is 362880, while the sum is 44.

The square root of 1581673643 is about 39770.2607861704. The cubic root of 1581673643 is about 1165.1243871190.

The spelling of 1581673643 in words is "one billion, five hundred eighty-one million, six hundred seventy-three thousand, six hundred forty-three".