21111048 has 48 divisors (see below), whose sum is σ = 65345280. Its totient is φ = 6031584.

The previous prime is 21111029. The next prime is 21111049. The reversal of 21111048 is 84011112.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21111048.

It is not an unprimeable number, because it can be changed into a prime (21111049) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20440 + ... + 21447.

It is an arithmetic number, because the mean of its divisors is an integer number (1361360).

Almost surely, 2^21111048 is an apocalyptic number.

21111048 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21111048 is an abundant number, since it is smaller than the sum of its proper divisors (44234232).

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

21111048 is a wasteful number, since it uses less digits than its factorization.

21111048 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41906 (or 41899 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 21111048 is about 4594.6760495164. The cubic root of 21111048 is about 276.3778693197.

Adding to 21111048 its product of nonzero digits (64), we get a palindrome (21111112).

It can be divided in two parts, 2111104 and 8, that added together give a palindrome (2111112).

The spelling of 21111048 in words is "twenty-one million, one hundred eleven thousand, forty-eight".