21911142 has 64 divisors (see below), whose sum is σ = 51114240. Its totient is φ = 6192000.

The previous prime is 21911137. The next prime is 21911143. The reversal of 21911142 is 24111912.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21911143) by changing a digit.

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, 126568 + ... + 126740.

It is an arithmetic number, because the mean of its divisors is an integer number (798660).

Almost surely, 2^21911142 is an apocalyptic number.

21911142 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21911142, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25557120).

21911142 is an abundant number, since it is smaller than the sum of its proper divisors (29203098).

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

21911142 is a wasteful number, since it uses less digits than its factorization.

21911142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309.

The product of its digits is 144, while the sum is 21.

The square root of 21911142 is about 4680.9338811823. The cubic root of 21911142 is about 279.8261761262.

It can be divided in two parts, 2191 and 1142, that added together give a palindrome (3333).

The spelling of 21911142 in words is "twenty-one million, nine hundred eleven thousand, one hundred forty-two".