21131110 has 64 divisors (see below), whose sum is σ = 51093504. Its totient is φ = 6076800.

The previous prime is 21131087. The next prime is 21131137. The reversal of 21131110 is 1113112.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8955 + ... + 11065.

It is an arithmetic number, because the mean of its divisors is an integer number (798336).

Almost surely, 2^21131110 is an apocalyptic number.

21131110 is an abundant number, since it is smaller than the sum of its proper divisors (29962394).

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

21131110 is a wasteful number, since it uses less digits than its factorization.

21131110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2149.

The product of its (nonzero) digits is 6, while the sum is 10.

The square root of 21131110 is about 4596.8587100323. The cubic root of 21131110 is about 276.4653896447.

Adding to 21131110 its reverse (1113112), we get a palindrome (22244222).

It can be divided in two parts, 2113 and 1110, that added together give a palindrome (3223).

The spelling of 21131110 in words is "twenty-one million, one hundred thirty-one thousand, one hundred ten".