21536501963 has 4 divisors (see below), whose sum is σ = 21901527480. Its totient is φ = 21171476448.

The previous prime is 21536501951. The next prime is 21536502011. The reversal of 21536501963 is 36910563512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21536501963 - 2¹⁰ = 21536500939 is a prime.

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 21536501963.

It is not an unprimeable number, because it can be changed into a prime (21536509963) 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 3 ways as a sum of consecutive naturals, for example, 182512670 + ... + 182512787.

It is an arithmetic number, because the mean of its divisors is an integer number (5475381870).

Almost surely, 2^21536501963 is an apocalyptic number.

21536501963 is a deficient number, since it is larger than the sum of its proper divisors (365025517).

21536501963 is an equidigital number, since it uses as much as digits as its factorization.

21536501963 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 365025516.

The product of its (nonzero) digits is 145800, while the sum is 41.

The spelling of 21536501963 in words is "twenty-one billion, five hundred thirty-six million, five hundred one thousand, nine hundred sixty-three".