203955973981 has 2 divisors, whose sum is σ = 203955973982. Its totient is φ = 203955973980.

The previous prime is 203955973913. The next prime is 203955973997. The reversal of 203955973981 is 189379559302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 177669837081 + 26286136900 = 421509^2 + 162130^2 .

It is a cyclic number.

It is not a de Polignac number, because 203955973981 - 2¹⁵ = 203955941213 is a prime.

It is a super-2 number, since 2×203955973981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (203955973901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 101977986990 + 101977986991.

It is an arithmetic number, because the mean of its divisors is an integer number (101977986991).

Almost surely, 2^203955973981 is an apocalyptic number.

It is an amenable number.

203955973981 is a deficient number, since it is larger than the sum of its proper divisors (1).

203955973981 is an equidigital number, since it uses as much as digits as its factorization.

203955973981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18370800, while the sum is 61.

The spelling of 203955973981 in words is "two hundred three billion, nine hundred fifty-five million, nine hundred seventy-three thousand, nine hundred eighty-one".