20991935563 has 8 divisors (see below), whose sum is σ = 22993195680. Its totient is φ = 19075835520.

The previous prime is 20991935539. The next prime is 20991935567. The reversal of 20991935563 is 36553919902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20991935563 - 2¹³ = 20991927371 is a prime.

It is a super-2 number, since 2×20991935563² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20991935563.

It is not an unprimeable number, because it can be changed into a prime (20991935567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21289503 + ... + 21290488.

It is an arithmetic number, because the mean of its divisors is an integer number (2874149460).

Almost surely, 2^20991935563 is an apocalyptic number.

20991935563 is a deficient number, since it is larger than the sum of its proper divisors (2001260117).

20991935563 is a wasteful number, since it uses less digits than its factorization.

20991935563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42580037.

The product of its (nonzero) digits is 1968300, while the sum is 52.

The spelling of 20991935563 in words is "twenty billion, nine hundred ninety-one million, nine hundred thirty-five thousand, five hundred sixty-three".