5951221981 has 2 divisors, whose sum is σ = 5951221982. Its totient is φ = 5951221980.

The previous prime is 5951221961. The next prime is 5951222023. The reversal of 5951221981 is 1891221595.

5951221981 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5207787225 + 743434756 = 72165^2 + 27266^2 .

It is a cyclic number.

It is not a de Polignac number, because 5951221981 - 2⁵ = 5951221949 is a prime.

It is a super-2 number, since 2×5951221981² = 70834086134275128722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5951221901) 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 as a sum of consecutive naturals, namely, 2975610990 + 2975610991.

It is an arithmetic number, because the mean of its divisors is an integer number (2975610991).

Almost surely, 2^5951221981 is an apocalyptic number.

It is an amenable number.

5951221981 is a deficient number, since it is larger than the sum of its proper divisors (1).

5951221981 is an equidigital number, since it uses as much as digits as its factorization.

5951221981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64800, while the sum is 43.

The square root of 5951221981 is about 77144.1636224024. The cubic root of 5951221981 is about 1812.1829913816.

The spelling of 5951221981 in words is "five billion, nine hundred fifty-one million, two hundred twenty-one thousand, nine hundred eighty-one".