21310042 has 8 divisors (see below), whose sum is σ = 34423956. Its totient is φ = 9835392.

The previous prime is 21310021. The next prime is 21310043. The reversal of 21310042 is 24001312.

It can be written as a sum of positive squares in 2 ways, for example, as 20875761 + 434281 = 4569^2 + 659^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-5 number, since 5×21310042⁵ (a number of 38 digits) contains 55555 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is not an unprimeable number, because it can be changed into a prime (21310043) 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 3 ways as a sum of consecutive naturals, for example, 409783 + ... + 409834.

Almost surely, 2^21310042 is an apocalyptic number.

21310042 is a deficient number, since it is larger than the sum of its proper divisors (13113914).

21310042 is a wasteful number, since it uses less digits than its factorization.

21310042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 819632.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21310042 is about 4616.2801041531. The cubic root of 21310042 is about 277.2435398071.

Adding to 21310042 its reverse (24001312), we get a palindrome (45311354).

The spelling of 21310042 in words is "twenty-one million, three hundred ten thousand, forty-two".