1581481685 has 16 divisors (see below), whose sum is σ = 2174570496. Its totient is φ = 1081603968.

The previous prime is 1581481667. The next prime is 1581481697. The reversal of 1581481685 is 5861841851.

It is a cyclic number.

It is not a de Polignac number, because 1581481685 - 2¹² = 1581477589 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45584 + ... + 72393.

It is an arithmetic number, because the mean of its divisors is an integer number (135910656).

Almost surely, 2^1581481685 is an apocalyptic number.

It is an amenable number.

1581481685 is a deficient number, since it is larger than the sum of its proper divisors (593088811).

1581481685 is a wasteful number, since it uses less digits than its factorization.

1581481685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118372.

The product of its digits is 307200, while the sum is 47.

The square root of 1581481685 is about 39767.8473769954. The cubic root of 1581481685 is about 1165.0772505523.

The spelling of 1581481685 in words is "one billion, five hundred eighty-one million, four hundred eighty-one thousand, six hundred eighty-five".