21643075215 has 12 divisors (see below), whose sum is σ = 37514663784. Its totient is φ = 11542973424.

The previous prime is 21643075211. The next prime is 21643075229. The reversal of 21643075215 is 51257034612.

21643075215 is a `hidden beast` number, since 2 + 1 + 6 + 430 + 7 + 5 + 215 = 666.

It is not a de Polignac number, because 21643075215 - 2² = 21643075211 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21643075215.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21643075211) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 240478569 + ... + 240478658.

It is an arithmetic number, because the mean of its divisors is an integer number (3126221982).

Almost surely, 2^21643075215 is an apocalyptic number.

21643075215 is a deficient number, since it is larger than the sum of its proper divisors (15871588569).

21643075215 is a wasteful number, since it uses less digits than its factorization.

21643075215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480957238 (or 480957235 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The spelling of 21643075215 in words is "twenty-one billion, six hundred forty-three million, seventy-five thousand, two hundred fifteen".