2108357981 has 2 divisors, whose sum is σ = 2108357982. Its totient is φ = 2108357980.

The previous prime is 2108357963. The next prime is 2108357987. The reversal of 2108357981 is 1897538012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1512509881 + 595848100 = 38891^2 + 24410^2 .

It is a cyclic number.

It is not a de Polignac number, because 2108357981 - 2¹⁸ = 2108095837 is a prime.

It is a super-2 number, since 2×2108357981² = 8890346752092792722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2108357987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1054178990 + 1054178991.

It is an arithmetic number, because the mean of its divisors is an integer number (1054178991).

Almost surely, 2^2108357981 is an apocalyptic number.

It is an amenable number.

2108357981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2108357981 is an equidigital number, since it uses as much as digits as its factorization.

2108357981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120960, while the sum is 44.

The square root of 2108357981 is about 45916.8594418216. The cubic root of 2108357981 is about 1282.2758139220.

The spelling of 2108357981 in words is "two billion, one hundred eight million, three hundred fifty-seven thousand, nine hundred eighty-one".