1581961885 has 8 divisors (see below), whose sum is σ = 2169547776. Its totient is φ = 1084773840.

The previous prime is 1581961853. The next prime is 1581961921. The reversal of 1581961885 is 5881691851.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1581961885 - 2⁵ = 1581961853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 22599421 + ... + 22599490.

It is an arithmetic number, because the mean of its divisors is an integer number (271193472).

Almost surely, 2^1581961885 is an apocalyptic number.

It is an amenable number.

1581961885 is a deficient number, since it is larger than the sum of its proper divisors (587585891).

1581961885 is an equidigital number, since it uses as much as digits as its factorization.

1581961885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45198923.

The product of its digits is 691200, while the sum is 52.

The square root of 1581961885 is about 39773.8844595295. The cubic root of 1581961885 is about 1165.1951597015.

The spelling of 1581961885 in words is "one billion, five hundred eighty-one million, nine hundred sixty-one thousand, eight hundred eighty-five".