21000010031 has 32 divisors (see below), whose sum is σ = 28209216000. Its totient is φ = 15097726080.

The previous prime is 21000010001. The next prime is 21000010037. The reversal of 21000010031 is 13001000012.

It is a cyclic number.

It is not a de Polignac number, because 21000010031 - 2⁶ = 21000009967 is a prime.

It is a super-2 number, since 2×21000010031² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000010037) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3018545 + ... + 3025493.

It is an arithmetic number, because the mean of its divisors is an integer number (881538000).

Almost surely, 2^21000010031 is an apocalyptic number.

21000010031 is a deficient number, since it is larger than the sum of its proper divisors (7209205969).

21000010031 is a wasteful number, since it uses less digits than its factorization.

21000010031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9999.

The product of its (nonzero) digits is 6, while the sum is 8.

Adding to 21000010031 its reverse (13001000012), we get a palindrome (34001010043).

The spelling of 21000010031 in words is "twenty-one billion, ten thousand, thirty-one".