21658138433 has 4 divisors (see below), whose sum is σ = 21768078420. Its totient is φ = 21548198448.

The previous prime is 21658138423. The next prime is 21658138451. The reversal of 21658138433 is 33483185612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21215961649 + 442176784 = 145657^2 + 21028^2 .

It is a cyclic number.

It is not a de Polignac number, because 21658138433 - 2¹⁰ = 21658137409 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21658138423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54969698 + ... + 54970091.

It is an arithmetic number, because the mean of its divisors is an integer number (5442019605).

Almost surely, 2^21658138433 is an apocalyptic number.

It is an amenable number.

21658138433 is a deficient number, since it is larger than the sum of its proper divisors (109939987).

21658138433 is a wasteful number, since it uses less digits than its factorization.

21658138433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109939986.

The product of its digits is 414720, while the sum is 44.

The spelling of 21658138433 in words is "twenty-one billion, six hundred fifty-eight million, one hundred thirty-eight thousand, four hundred thirty-three".