1081386491866 has 4 divisors (see below), whose sum is σ = 1622079737802. Its totient is φ = 540693245932.

The previous prime is 1081386491863. The next prime is 1081386491923. The reversal of 1081386491866 is 6681946831801.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1026057573025 + 55328918841 = 1012945^2 + 235221^2 .

It is not an unprimeable number, because it can be changed into a prime (1081386491863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 270346622965 + ... + 270346622968.

Almost surely, 2^{1081386491866} is an apocalyptic number.

1081386491866 is a deficient number, since it is larger than the sum of its proper divisors (540693245936).

1081386491866 is an equidigital number, since it uses as much as digits as its factorization.

1081386491866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540693245935.

The product of its (nonzero) digits is 11943936, while the sum is 61.

The spelling of 1081386491866 in words is "one trillion, eighty-one billion, three hundred eighty-six million, four hundred ninety-one thousand, eight hundred sixty-six".