1001861811 has 32 divisors (see below), whose sum is σ = 1616256000. Its totient is φ = 610926624.

The previous prime is 1001861803. The next prime is 1001861843. The reversal of 1001861811 is 1181681001.

It is not a de Polignac number, because 1001861811 - 2³ = 1001861803 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1001861801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18795 + ... + 48548.

It is an arithmetic number, because the mean of its divisors is an integer number (50508000).

Almost surely, 2^1001861811 is an apocalyptic number.

1001861811 is a deficient number, since it is larger than the sum of its proper divisors (614394189).

1001861811 is a wasteful number, since it uses less digits than its factorization.

1001861811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67400 (or 67394 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 27.

The square root of 1001861811 is about 31652.2007291752. The cubic root of 1001861811 is about 1000.6202189156.

The spelling of 1001861811 in words is "one billion, one million, eight hundred sixty-one thousand, eight hundred eleven".