21331242 has 16 divisors (see below), whose sum is σ = 47402880. Its totient is φ = 7110396.

The previous prime is 21331217. The next prime is 21331267. The reversal of 21331242 is 24213312.

It is an interprime number because it is at equal distance from previous prime (21331217) and next prime (21331267).

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

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 7 ways as a sum of consecutive naturals, for example, 197458 + ... + 197565.

It is an arithmetic number, because the mean of its divisors is an integer number (2962680).

Almost surely, 2^21331242 is an apocalyptic number.

21331242 is an abundant number, since it is smaller than the sum of its proper divisors (26071638).

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

21331242 is a wasteful number, since it uses less digits than its factorization.

21331242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395034 (or 395028 counting only the distinct ones).

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

The square root of 21331242 is about 4618.5757544940. The cubic root of 21331242 is about 277.3354466344.

Adding to 21331242 its reverse (24213312), we get a palindrome (45544554).

It can be divided in two parts, 2133 and 1242, that added together give a cube (3375 = 15³).

The spelling of 21331242 in words is "twenty-one million, three hundred thirty-one thousand, two hundred forty-two".