7001801981 has 4 divisors (see below), whose sum is σ = 7002119964. Its totient is φ = 7001484000.

The previous prime is 7001801957. The next prime is 7001801993. The reversal of 7001801981 is 1891081007.

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 5740486756 + 1261315225 = 75766^2 + 35515^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7001801981 is a prime.

It is a super-2 number, since 2×7001801981² = 98050461962271048722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7001801921) 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, 123290 + ... + 170891.

It is an arithmetic number, because the mean of its divisors is an integer number (1750529991).

Almost surely, 2^7001801981 is an apocalyptic number.

It is an amenable number.

7001801981 is a deficient number, since it is larger than the sum of its proper divisors (317983).

7001801981 is a wasteful number, since it uses less digits than its factorization.

7001801981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 317982.

The product of its (nonzero) digits is 4032, while the sum is 35.

The square root of 7001801981 is about 83676.7708566720. The cubic root of 7001801981 is about 1913.0953146724.

Adding to 7001801981 its reverse (1891081007), we get a palindrome (8892882988).

The spelling of 7001801981 in words is "seven billion, one million, eight hundred one thousand, nine hundred eighty-one".