1981124281 has 4 divisors (see below), whose sum is σ = 2085394000. Its totient is φ = 1876854564.

The previous prime is 1981124269. The next prime is 1981124287. The reversal of 1981124281 is 1824211891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1824211891 = 9767 ⋅186773.

It is a cyclic number.

It is not a de Polignac number, because 1981124281 - 2⁹ = 1981123769 is a prime.

It is a super-2 number, since 2×1981124281² = 7849706833535533922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1981124281.

It is not an unprimeable number, because it can be changed into a prime (1981124287) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 52134831 + ... + 52134868.

It is an arithmetic number, because the mean of its divisors is an integer number (521348500).

Almost surely, 2^1981124281 is an apocalyptic number.

It is an amenable number.

1981124281 is a deficient number, since it is larger than the sum of its proper divisors (104269719).

1981124281 is a wasteful number, since it uses less digits than its factorization.

1981124281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104269718.

The product of its digits is 9216, while the sum is 37.

The square root of 1981124281 is about 44509.8222980052. The cubic root of 1981124281 is about 1255.9448620179.

The spelling of 1981124281 in words is "one billion, nine hundred eighty-one million, one hundred twenty-four thousand, two hundred eighty-one".