1981758392 has 8 divisors (see below), whose sum is σ = 3715797000. Its totient is φ = 990879192.

The previous prime is 1981758377. The next prime is 1981758397. The reversal of 1981758392 is 2938571891.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981758397) by changing a digit.

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 as a sum of consecutive naturals, namely, 123859892 + ... + 123859907.

It is an arithmetic number, because the mean of its divisors is an integer number (464474625).

Almost surely, 2^1981758392 is an apocalyptic number.

It is an amenable number.

1981758392 is a deficient number, since it is larger than the sum of its proper divisors (1734038608).

1981758392 is a wasteful number, since it uses less digits than its factorization.

1981758392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247719805 (or 247719801 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 53.

The square root of 1981758392 is about 44516.9449985059. The cubic root of 1981758392 is about 1256.0788471334.

The spelling of 1981758392 in words is "one billion, nine hundred eighty-one million, seven hundred fifty-eight thousand, three hundred ninety-two".