7881981 has 8 divisors (see below), whose sum is σ = 10554240. Its totient is φ = 5232192.

The previous prime is 7881977. The next prime is 7881983. The reversal of 7881981 is 1891887.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 7881981 - 2² = 7881977 is a prime.

It is a super-2 number, since 2×7881981² = 124251248968722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7881983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4780 + ... + 6213.

It is an arithmetic number, because the mean of its divisors is an integer number (1319280).

Almost surely, 2^7881981 is an apocalyptic number.

It is an amenable number.

7881981 is a deficient number, since it is larger than the sum of its proper divisors (2672259).

7881981 is a wasteful number, since it uses less digits than its factorization.

7881981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11235.

The product of its digits is 32256, while the sum is 42.

The square root of 7881981 is about 2807.4865983652. The cubic root of 7881981 is about 199.0116320229.

The spelling of 7881981 in words is "seven million, eight hundred eighty-one thousand, nine hundred eighty-one".