21533405042 has 8 divisors (see below), whose sum is σ = 32329662636. Its totient is φ = 10756850832.

The previous prime is 21533405027. The next prime is 21533405063. The reversal of 21533405042 is 24050433512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16412428321 + 5120976721 = 128111^2 + 71561^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21533404996 and 21533405014.

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, 4923113 + ... + 4927484.

Almost surely, 2^21533405042 is an apocalyptic number.

21533405042 is a deficient number, since it is larger than the sum of its proper divisors (10796257594).

21533405042 is a wasteful number, since it uses less digits than its factorization.

21533405042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9851692.

The product of its (nonzero) digits is 14400, while the sum is 29.

Adding to 21533405042 its reverse (24050433512), we get a palindrome (45583838554).

The spelling of 21533405042 in words is "twenty-one billion, five hundred thirty-three million, four hundred five thousand, forty-two".