21423040042 has 8 divisors (see below), whose sum is σ = 34024828356. Its totient is φ = 10081430592.

The previous prime is 21423040033. The next prime is 21423040043. The reversal of 21423040042 is 24004032412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20289438481 + 1133601561 = 142441^2 + 33669^2 .

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

It is a super-2 number, since 2×21423040042² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21423039995 and 21423040022.

It is not an unprimeable number, because it can be changed into a prime (21423040043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 315044673 + ... + 315044740.

Almost surely, 2^21423040042 is an apocalyptic number.

21423040042 is a deficient number, since it is larger than the sum of its proper divisors (12601788314).

21423040042 is a wasteful number, since it uses less digits than its factorization.

21423040042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 630089432.

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21423040042 its reverse (24004032412), we get a palindrome (45427072454).

The spelling of 21423040042 in words is "twenty-one billion, four hundred twenty-three million, forty thousand, forty-two".