21123131310 has 24 divisors (see below), whose sum is σ = 54920141640. Its totient is φ = 5632834992.

The previous prime is 21123131303. The next prime is 21123131327. The reversal of 21123131310 is 1313132112.

It is a super-2 number, since 2×21123131310² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 117350640 + ... + 117350819.

It is an arithmetic number, because the mean of its divisors is an integer number (2288339235).

Almost surely, 2^21123131310 is an apocalyptic number.

21123131310 is an abundant number, since it is smaller than the sum of its proper divisors (33797010330).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21123131310 is a wasteful number, since it uses less digits than its factorization.

21123131310 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234701472 (or 234701469 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

Adding to 21123131310 its reverse (1313132112), we get a palindrome (22436263422).

The spelling of 21123131310 in words is "twenty-one billion, one hundred twenty-three million, one hundred thirty-one thousand, three hundred ten".