21231342 has 64 divisors (see below), whose sum is σ = 53176320. Its totient is φ = 6220800.

The previous prime is 21231313. The next prime is 21231359. The reversal of 21231342 is 24313212.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17838 + ... + 18990.

It is an arithmetic number, because the mean of its divisors is an integer number (830880).

Almost surely, 2^21231342 is an apocalyptic number.

21231342 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 21231342, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26588160).

21231342 is an abundant number, since it is smaller than the sum of its proper divisors (31944978).

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

21231342 is a wasteful number, since it uses less digits than its factorization.

21231342 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1206 (or 1200 counting only the distinct ones).

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

The square root of 21231342 is about 4607.7480399866. The cubic root of 21231342 is about 276.9018232620.

Adding to 21231342 its reverse (24313212), we get a palindrome (45544554).

The spelling of 21231342 in words is "twenty-one million, two hundred thirty-one thousand, three hundred forty-two".