7910111981 has 4 divisors (see below), whose sum is σ = 7928380572. Its totient is φ = 7891843392.

The previous prime is 7910111969. The next prime is 7910112029. The reversal of 7910111981 is 1891110197.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 835788100 + 7074323881 = 28910^2 + 84109^2 .

It is a cyclic number.

It is not a de Polignac number, because 7910111981 - 2¹⁸ = 7909849837 is a prime.

It is a super-2 number, since 2×7910111981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7910111941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9133646 + ... + 9134511.

It is an arithmetic number, because the mean of its divisors is an integer number (1982095143).

Almost surely, 2^7910111981 is an apocalyptic number.

It is an amenable number.

7910111981 is a deficient number, since it is larger than the sum of its proper divisors (18268591).

7910111981 is a wasteful number, since it uses less digits than its factorization.

7910111981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18268590.

The product of its (nonzero) digits is 4536, while the sum is 38.

The square root of 7910111981 is about 88938.8103192302. The cubic root of 7910111981 is about 1992.4811002459.

The spelling of 7910111981 in words is "seven billion, nine hundred ten million, one hundred eleven thousand, nine hundred eighty-one".