21123303031 has 4 divisors (see below), whose sum is σ = 21129322864. Its totient is φ = 21117283200.

The previous prime is 21123302969. The next prime is 21123303037. The reversal of 21123303031 is 13030332112.

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 21123303031 - 2¹³ = 21123294839 is a prime.

It is a super-2 number, since 2×21123303031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123303037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3004650 + ... + 3011671.

It is an arithmetic number, because the mean of its divisors is an integer number (5282330716).

Almost surely, 2^21123303031 is an apocalyptic number.

21123303031 is a deficient number, since it is larger than the sum of its proper divisors (6019833).

21123303031 is an equidigital number, since it uses as much as digits as its factorization.

21123303031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6019832.

The product of its (nonzero) digits is 324, while the sum is 19.

Adding to 21123303031 its reverse (13030332112), we get a palindrome (34153635143).

The spelling of 21123303031 in words is "twenty-one billion, one hundred twenty-three million, three hundred three thousand, thirty-one".