21051342 has 24 divisors (see below), whose sum is σ = 49120344. Its totient is φ = 6477264.

The previous prime is 21051341. The next prime is 21051343. The reversal of 21051342 is 24315012.

It is an interprime number because it is at equal distance from previous prime (21051341) and next prime (21051343).

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 (21051341) 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 11 ways as a sum of consecutive naturals, for example, 44748 + ... + 45215.

It is an arithmetic number, because the mean of its divisors is an integer number (2046681).

Almost surely, 2^21051342 is an apocalyptic number.

21051342 is an abundant number, since it is smaller than the sum of its proper divisors (28069002).

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

21051342 is a wasteful number, since it uses less digits than its factorization.

21051342 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89984 (or 89981 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21051342 is about 4588.1741466514. The cubic root of 21051342 is about 276.1170738360.

Adding to 21051342 its reverse (24315012), we get a palindrome (45366354).

The spelling of 21051342 in words is "twenty-one million, fifty-one thousand, three hundred forty-two".