2109953981 has 2 divisors, whose sum is σ = 2109953982. Its totient is φ = 2109953980.

The previous prime is 2109953977. The next prime is 2109954029. The reversal of 2109953981 is 1893599012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1657711225 + 452242756 = 40715^2 + 21266^2 .

It is a cyclic number.

It is not a de Polignac number, because 2109953981 - 2² = 2109953977 is a prime.

It is a super-2 number, since 2×2109953981² = 8903811603875496722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2109953081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1054976990 + 1054976991.

It is an arithmetic number, because the mean of its divisors is an integer number (1054976991).

Almost surely, 2^2109953981 is an apocalyptic number.

It is an amenable number.

2109953981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2109953981 is an equidigital number, since it uses as much as digits as its factorization.

2109953981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 174960, while the sum is 47.

The square root of 2109953981 is about 45934.2353914812. The cubic root of 2109953981 is about 1282.5992877723.

The spelling of 2109953981 in words is "two billion, one hundred nine million, nine hundred fifty-three thousand, nine hundred eighty-one".