6859999981 has 2 divisors, whose sum is σ = 6859999982. Its totient is φ = 6859999980.

The previous prime is 6859999973. The next prime is 6860000003. The reversal of 6859999981 is 1899999586.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5204323881 + 1655676100 = 72141^2 + 40690^2 .

It is a cyclic number.

It is not a de Polignac number, because 6859999981 - 2³ = 6859999973 is a prime.

It is a super-2 number, since 2×6859999981² = 94119199478640000722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6859999901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3429999990 + 3429999991.

It is an arithmetic number, because the mean of its divisors is an integer number (3429999991).

Almost surely, 2^6859999981 is an apocalyptic number.

It is an amenable number.

6859999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

6859999981 is an equidigital number, since it uses as much as digits as its factorization.

6859999981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 113374080, while the sum is 73.

The square root of 6859999981 is about 82825.1168486951. The cubic root of 6859999981 is about 1900.0923298622.

The spelling of 6859999981 in words is "six billion, eight hundred fifty-nine million, nine hundred ninety-nine thousand, nine hundred eighty-one".