21031001001 has 16 divisors (see below), whose sum is σ = 31163502720. Its totient is φ = 14017758480.

The previous prime is 21031000973. The next prime is 21031001039. The reversal of 21031001001 is 10010013012.

It is not a de Polignac number, because 21031001001 - 2⁹ = 21031000489 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21031001041) 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 15 ways as a sum of consecutive naturals, for example, 55956 + ... + 212586.

It is an arithmetic number, because the mean of its divisors is an integer number (1947718920).

Almost surely, 2^21031001001 is an apocalyptic number.

It is an amenable number.

21031001001 is a deficient number, since it is larger than the sum of its proper divisors (10132501719).

21031001001 is a wasteful number, since it uses less digits than its factorization.

21031001001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161613 (or 161607 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 9.

Adding to 21031001001 its reverse (10010013012), we get a palindrome (31041014013).

The spelling of 21031001001 in words is "twenty-one billion, thirty-one million, one thousand, one".