21033164987 has 4 divisors (see below), whose sum is σ = 21033785136. Its totient is φ = 21032544840.

The previous prime is 21033164981. The next prime is 21033164989. The reversal of 21033164987 is 78946133012.

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 21033164987 - 2¹⁴ = 21033148603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21033164981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 256064 + ... + 328077.

It is an arithmetic number, because the mean of its divisors is an integer number (5258446284).

Almost surely, 2^21033164987 is an apocalyptic number.

21033164987 is a deficient number, since it is larger than the sum of its proper divisors (620149).

21033164987 is an equidigital number, since it uses as much as digits as its factorization.

21033164987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 620148.

The product of its (nonzero) digits is 217728, while the sum is 44.

Adding to 21033164987 its reverse (78946133012), we get a palindrome (99979297999).

The spelling of 21033164987 in words is "twenty-one billion, thirty-three million, one hundred sixty-four thousand, nine hundred eighty-seven".