21002023031 has 4 divisors (see below), whose sum is σ = 22911297864. Its totient is φ = 19092748200.

The previous prime is 21002023013. The next prime is 21002023061. The reversal of 21002023031 is 13032020012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21002023031 - 2⁶ = 21002022967 is a prime.

It is a super-2 number, since 2×21002023031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002022997 and 21002023015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002023001) 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 3 ways as a sum of consecutive naturals, for example, 954637400 + ... + 954637421.

It is an arithmetic number, because the mean of its divisors is an integer number (5727824466).

Almost surely, 2^21002023031 is an apocalyptic number.

21002023031 is a deficient number, since it is larger than the sum of its proper divisors (1909274833).

21002023031 is a wasteful number, since it uses less digits than its factorization.

21002023031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1909274832.

The product of its (nonzero) digits is 72, while the sum is 14.

Adding to 21002023031 its reverse (13032020012), we get a palindrome (34034043043).

The spelling of 21002023031 in words is "twenty-one billion, two million, twenty-three thousand, thirty-one".