1981791526 has 32 divisors (see below), whose sum is σ = 3544547328. Its totient is φ = 819102240.

The previous prime is 1981791509. The next prime is 1981791557. The reversal of 1981791526 is 6251971891.

It is a self number, because there is not a number n which added to its sum of digits gives 1981791526.

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, 32550 + ... + 70873.

It is an arithmetic number, because the mean of its divisors is an integer number (110767104).

Almost surely, 2^1981791526 is an apocalyptic number.

1981791526 is a deficient number, since it is larger than the sum of its proper divisors (1562755802).

1981791526 is a wasteful number, since it uses less digits than its factorization.

1981791526 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103516.

The product of its digits is 272160, while the sum is 49.

The square root of 1981791526 is about 44517.3171473754. The cubic root of 1981791526 is about 1256.0858474292.

The spelling of 1981791526 in words is "one billion, nine hundred eighty-one million, seven hundred ninety-one thousand, five hundred twenty-six".