1081661381 has 2 divisors, whose sum is σ = 1081661382. Its totient is φ = 1081661380.

The previous prime is 1081661369. The next prime is 1081661387. The reversal of 1081661381 is 1831661801.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 867302500 + 214358881 = 29450^2 + 14641^2 .

It is a cyclic number.

It is not a de Polignac number, because 1081661381 - 2¹⁴ = 1081644997 is a prime.

It is a super-2 number, since 2×1081661381² = 2339982686293654322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1081661387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 540830690 + 540830691.

It is an arithmetic number, because the mean of its divisors is an integer number (540830691).

Almost surely, 2^1081661381 is an apocalyptic number.

It is an amenable number.

1081661381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1081661381 is an equidigital number, since it uses as much as digits as its factorization.

1081661381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 1081661381 is about 32888.6208436900. The cubic root of 1081661381 is about 1026.5113950518.

The spelling of 1081661381 in words is "one billion, eighty-one million, six hundred sixty-one thousand, three hundred eighty-one".