21508264730 has 16 divisors (see below), whose sum is σ = 38974710600. Its totient is φ = 8545564992.

The previous prime is 21508264711. The next prime is 21508264747. The reversal of 21508264730 is 3746280512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 13811185441 + 7697079289 = 117521^2 + 87733^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7216049 + ... + 7219028.

Almost surely, 2^21508264730 is an apocalyptic number.

21508264730 is a deficient number, since it is larger than the sum of its proper divisors (17466445870).

21508264730 is a wasteful number, since it uses less digits than its factorization.

21508264730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14435233.

The product of its (nonzero) digits is 80640, while the sum is 38.

The spelling of 21508264730 in words is "twenty-one billion, five hundred eight million, two hundred sixty-four thousand, seven hundred thirty".