21123030331 has 4 divisors (see below), whose sum is σ = 22747878832. Its totient is φ = 19498181832.

The previous prime is 21123030277. The next prime is 21123030377. The reversal of 21123030331 is 13303032112.

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 21123030331 - 2³¹ = 18975546683 is a prime.

It is a super-2 number, since 2×21123030331² (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 = 21123030299 and 21123030308.

It is not an unprimeable number, because it can be changed into a prime (21123030031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 812424231 + ... + 812424256.

It is an arithmetic number, because the mean of its divisors is an integer number (5686969708).

Almost surely, 2^21123030331 is an apocalyptic number.

21123030331 is a deficient number, since it is larger than the sum of its proper divisors (1624848501).

21123030331 is a wasteful number, since it uses less digits than its factorization.

21123030331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1624848500.

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

Adding to 21123030331 its reverse (13303032112), we get a palindrome (34426062443).

The spelling of 21123030331 in words is "twenty-one billion, one hundred twenty-three million, thirty thousand, three hundred thirty-one".