1001668781 has 8 divisors (see below), whose sum is σ = 1075529664. Its totient is φ = 929467840.

The previous prime is 1001668777. The next prime is 1001668793. The reversal of 1001668781 is 1878661001.

1001668781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1001668781 - 2² = 1001668777 is a prime.

It is a super-2 number, since 2×1001668781² = 2006680693660051922, 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 (1001668721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 413735 + ... + 416148.

It is an arithmetic number, because the mean of its divisors is an integer number (134441208).

Almost surely, 2^1001668781 is an apocalyptic number.

It is an amenable number.

1001668781 is a deficient number, since it is larger than the sum of its proper divisors (73860883).

1001668781 is an equidigital number, since it uses as much as digits as its factorization.

1001668781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829971.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 1001668781 is about 31649.1513472320. The cubic root of 1001668781 is about 1000.5559511943. Note that the first 3 decimals are identical.

The spelling of 1001668781 in words is "one billion, one million, six hundred sixty-eight thousand, seven hundred eighty-one".