1001000861 has 6 divisors (see below), whose sum is σ = 1164429630. Its totient is φ = 858000696.

The previous prime is 1001000843. The next prime is 1001000867. The reversal of 1001000861 is 1680001001.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 966836836 + 34164025 = 31094^2 + 5845^2 .

It is not a de Polignac number, because 1001000861 - 2⁶ = 1001000797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001000867) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10214246 + ... + 10214343.

It is an arithmetic number, because the mean of its divisors is an integer number (194071605).

Almost surely, 2^1001000861 is an apocalyptic number.

It is an amenable number.

1001000861 is a deficient number, since it is larger than the sum of its proper divisors (163428769).

1001000861 is an equidigital number, since it uses as much as digits as its factorization.

1001000861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20428603 (or 20428596 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 1001000861 is about 31638.5976459134. The cubic root of 1001000861 is about 1000.3335090927. Note that the first 3 decimals are identical.

Adding to 1001000861 its reverse (1680001001), we get a palindrome (2681001862).

The spelling of 1001000861 in words is "one billion, one million, eight hundred sixty-one", and thus it is an aban number.