21404340242 has 8 divisors (see below), whose sum is σ = 33213631500. Its totient is φ = 10333129744.

The previous prime is 21404340187. The next prime is 21404340289. The reversal of 21404340242 is 24204340412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21403397401 + 942841 = 146299^2 + 971^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 184520117 + ... + 184520232.

Almost surely, 2^21404340242 is an apocalyptic number.

21404340242 is a deficient number, since it is larger than the sum of its proper divisors (11809291258).

21404340242 is a wasteful number, since it uses less digits than its factorization.

21404340242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 369040380.

The product of its (nonzero) digits is 6144, while the sum is 26.

Adding to 21404340242 its reverse (24204340412), we get a palindrome (45608680654).

The spelling of 21404340242 in words is "twenty-one billion, four hundred four million, three hundred forty thousand, two hundred forty-two".