21605774308 has 6 divisors (see below), whose sum is σ = 37810105046. Its totient is φ = 10802887152.

The previous prime is 21605774269. The next prime is 21605774321. The reversal of 21605774308 is 80347750612.

It can be written as a sum of positive squares in only one way, i.e., 21583135744 + 22638564 = 146912^2 + 4758^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2700721785 + ... + 2700721792.

Almost surely, 2^21605774308 is an apocalyptic number.

It is an amenable number.

21605774308 is a deficient number, since it is larger than the sum of its proper divisors (16204330738).

21605774308 is a wasteful number, since it uses less digits than its factorization.

21605774308 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5401443581 (or 5401443579 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 43.

The spelling of 21605774308 in words is "twenty-one billion, six hundred five million, seven hundred seventy-four thousand, three hundred eight".