21311031100 has 36 divisors (see below), whose sum is σ = 46424934864. Its totient is φ = 8491233280.

The previous prime is 21311031083. The next prime is 21311031107. The reversal of 21311031100 is 113011312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311031107) 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 11 ways as a sum of consecutive naturals, for example, 388912 + ... + 440311.

It is an arithmetic number, because the mean of its divisors is an integer number (1289581524).

Almost surely, 2^21311031100 is an apocalyptic number.

21311031100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21311031100 is an abundant number, since it is smaller than the sum of its proper divisors (25113903764).

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

21311031100 is a wasteful number, since it uses less digits than its factorization.

21311031100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829494 (or 829487 counting only the distinct ones).

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

Adding to 21311031100 its reverse (113011312), we get a palindrome (21424042412).

The spelling of 21311031100 in words is "twenty-one billion, three hundred eleven million, thirty-one thousand, one hundred".