1981033261 has 2 divisors, whose sum is σ = 1981033262. Its totient is φ = 1981033260.

The previous prime is 1981033199. The next prime is 1981033303. The reversal of 1981033261 is 1623301891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1862354025 + 118679236 = 43155^2 + 10894^2 .

It is an emirp because it is prime and its reverse (1623301891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1981033261 - 2⁹ = 1981032749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1981033661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990516630 + 990516631.

It is an arithmetic number, because the mean of its divisors is an integer number (990516631).

Almost surely, 2^1981033261 is an apocalyptic number.

It is an amenable number.

1981033261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981033261 is an equidigital number, since it uses as much as digits as its factorization.

1981033261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 1981033261 is about 44508.7998153174. The cubic root of 1981033261 is about 1255.9256275099.

The spelling of 1981033261 in words is "one billion, nine hundred eighty-one million, thirty-three thousand, two hundred sixty-one".