21515030663 has 16 divisors (see below), whose sum is σ = 26044340544. Its totient is φ = 17350433280.

The previous prime is 21515030633. The next prime is 21515030743. The reversal of 21515030663 is 36603051512.

It is a cyclic number.

It is not a de Polignac number, because 21515030663 - 2¹² = 21515026567 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21515030633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 316133 + ... + 378113.

It is an arithmetic number, because the mean of its divisors is an integer number (1627771284).

Almost surely, 2^21515030663 is an apocalyptic number.

21515030663 is a deficient number, since it is larger than the sum of its proper divisors (4529309881).

21515030663 is a wasteful number, since it uses less digits than its factorization.

21515030663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64922.

The product of its (nonzero) digits is 16200, while the sum is 32.

The spelling of 21515030663 in words is "twenty-one billion, five hundred fifteen million, thirty thousand, six hundred sixty-three".