21433434021 has 12 divisors (see below), whose sum is σ = 30981027948. Its totient is φ = 14278976064.

The previous prime is 21433433993. The next prime is 21433434023. The reversal of 21433434021 is 12043433412.

21433434021 is a `hidden beast` number, since 214 + 3 + 3 + 43 + 402 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 9923148225 + 11510285796 = 99615^2 + 107286^2 .

It is not a de Polignac number, because 21433434021 - 2⁹ = 21433433509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21433434023) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 818050 + ... + 843843.

It is an arithmetic number, because the mean of its divisors is an integer number (2581752329).

Almost surely, 2^21433434021 is an apocalyptic number.

It is an amenable number.

21433434021 is a deficient number, since it is larger than the sum of its proper divisors (9547593927).

21433434021 is a wasteful number, since it uses less digits than its factorization.

21433434021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1663332 (or 1663329 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 27.

Adding to 21433434021 its reverse (12043433412), we get a palindrome (33476867433).

The spelling of 21433434021 in words is "twenty-one billion, four hundred thirty-three million, four hundred thirty-four thousand, twenty-one".