21132342 has 96 divisors (see below), whose sum is σ = 58106880. Its totient is φ = 5391360.

The previous prime is 21132341. The next prime is 21132383. The reversal of 21132342 is 24323112.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21132341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 109398 + ... + 109590.

It is an arithmetic number, because the mean of its divisors is an integer number (605280).

Almost surely, 2^21132342 is an apocalyptic number.

21132342 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 21132342, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29053440).

21132342 is an abundant number, since it is smaller than the sum of its proper divisors (36974538).

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

21132342 is a wasteful number, since it uses less digits than its factorization.

21132342 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298 (or 295 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 21132342 is about 4596.9927126329. The cubic root of 21132342 is about 276.4707624299.

Adding to 21132342 its reverse (24323112), we get a palindrome (45455454).

The spelling of 21132342 in words is "twenty-one million, one hundred thirty-two thousand, three hundred forty-two".