21315342 has 16 divisors (see below), whose sum is σ = 44484480. Its totient is φ = 6796152.

The previous prime is 21315341. The next prime is 21315353. The reversal of 21315342 is 24351312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315341) 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 7 ways as a sum of consecutive naturals, for example, 77092 + ... + 77367.

It is an arithmetic number, because the mean of its divisors is an integer number (2780280).

Almost surely, 2^21315342 is an apocalyptic number.

21315342 is an abundant number, since it is smaller than the sum of its proper divisors (23169138).

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

21315342 is a wasteful number, since it uses less digits than its factorization.

21315342 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154487.

The product of its digits is 720, while the sum is 21.

The square root of 21315342 is about 4616.8541237514. The cubic root of 21315342 is about 277.2665222264.

Adding to 21315342 its reverse (24351312), we get a palindrome (45666654).

It can be divided in two parts, 213 and 15342, that multiplied together give a triangular number (3267846 = T₂₅₅₆).

The spelling of 21315342 in words is "twenty-one million, three hundred fifteen thousand, three hundred forty-two".