21001131031 has 2 divisors, whose sum is σ = 21001131032. Its totient is φ = 21001131030.

The previous prime is 21001131023. The next prime is 21001131049. The reversal of 21001131031 is 13013110012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21001131031 - 2³ = 21001131023 is a prime.

It is a super-2 number, since 2×21001131031² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001131061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500565515 + 10500565516.

It is an arithmetic number, because the mean of its divisors is an integer number (10500565516).

Almost surely, 2^21001131031 is an apocalyptic number.

21001131031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001131031 is an equidigital number, since it uses as much as digits as its factorization.

21001131031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18, while the sum is 13.

Adding to 21001131031 its reverse (13013110012), we get a palindrome (34014241043).

The spelling of 21001131031 in words is "twenty-one billion, one million, one hundred thirty-one thousand, thirty-one".