1011978181 has 4 divisors (see below), whose sum is σ = 1012250592. Its totient is φ = 1011705772.

The previous prime is 1011978169. The next prime is 1011978203. The reversal of 1011978181 is 1818791101.

It is a happy number.

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: 1818791101 = 47 ⋅38697683.

It is a cyclic number.

It is not a de Polignac number, because 1011978181 - 2⁹ = 1011977669 is a prime.

It is a super-2 number, since 2×1011978181² = 2048199677640137522, 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 1011978181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1011978581) 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, 130555 + ... + 138088.

It is an arithmetic number, because the mean of its divisors is an integer number (253062648).

Almost surely, 2^1011978181 is an apocalyptic number.

It is an amenable number.

1011978181 is a deficient number, since it is larger than the sum of its proper divisors (272411).

1011978181 is an equidigital number, since it uses as much as digits as its factorization.

1011978181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272410.

The product of its (nonzero) digits is 4032, while the sum is 37.

The square root of 1011978181 is about 31811.6045021310. The cubic root of 1011978181 is about 1003.9768903772.

The spelling of 1011978181 in words is "one billion, eleven million, nine hundred seventy-eight thousand, one hundred eighty-one".