1981531536 has 20 divisors (see below), whose sum is σ = 5118956592. Its totient is φ = 660510496.

The previous prime is 1981531529. The next prime is 1981531537. The reversal of 1981531536 is 6351351891.

It is not an unprimeable number, because it can be changed into a prime (1981531537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20640906 + ... + 20641001.

Almost surely, 2^1981531536 is an apocalyptic number.

1981531536 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1981531536 is an abundant number, since it is smaller than the sum of its proper divisors (3137425056).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1981531536 is a wasteful number, since it uses less digits than its factorization.

1981531536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41281918 (or 41281912 counting only the distinct ones).

The product of its digits is 97200, while the sum is 42.

The square root of 1981531536 is about 44514.3969519975. The cubic root of 1981531536 is about 1256.0309166528.

The spelling of 1981531536 in words is "one billion, nine hundred eighty-one million, five hundred thirty-one thousand, five hundred thirty-six".