21405332149 has 4 divisors (see below), whose sum is σ = 21420525420. Its totient is φ = 21390138880.

The previous prime is 21405332141. The next prime is 21405332159. The reversal of 21405332149 is 94123350412.

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 2303328049 + 19102004100 = 47993^2 + 138210^2 .

It is a cyclic number.

It is not a de Polignac number, because 21405332149 - 2³ = 21405332141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21405332141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7594522 + ... + 7597339.

It is an arithmetic number, because the mean of its divisors is an integer number (5355131355).

Almost surely, 2^21405332149 is an apocalyptic number.

It is an amenable number.

21405332149 is a deficient number, since it is larger than the sum of its proper divisors (15193271).

21405332149 is a wasteful number, since it uses less digits than its factorization.

21405332149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15193270.

The product of its (nonzero) digits is 25920, while the sum is 34.

The spelling of 21405332149 in words is "twenty-one billion, four hundred five million, three hundred thirty-two thousand, one hundred forty-nine".