1012668781 has 4 divisors (see below), whose sum is σ = 1012856572. Its totient is φ = 1012480992.

The previous prime is 1012668739. The next prime is 1012668829. The reversal of 1012668781 is 1878662101.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1878662101 = 179 ⋅10495319.

It can be written as a sum of positive squares in 2 ways, for example, as 875568100 + 137100681 = 29590^2 + 11709^2 .

It is a cyclic number.

It is not a de Polignac number, because 1012668781 - 2⁷ = 1012668653 is a prime.

It is a super-2 number, since 2×1012668781² = 2050996120024051922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1012668731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85560 + ... + 96673.

It is an arithmetic number, because the mean of its divisors is an integer number (253214143).

Almost surely, 2^1012668781 is an apocalyptic number.

It is an amenable number.

1012668781 is a deficient number, since it is larger than the sum of its proper divisors (187791).

1012668781 is an equidigital number, since it uses as much as digits as its factorization.

1012668781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187790.

The product of its (nonzero) digits is 32256, while the sum is 40.

The square root of 1012668781 is about 31822.4571804253. The cubic root of 1012668781 is about 1004.2052183505.

The spelling of 1012668781 in words is "one billion, twelve million, six hundred sixty-eight thousand, seven hundred eighty-one".