21198082729 has 4 divisors (see below), whose sum is σ = 21232329040. Its totient is φ = 21163836420.

The previous prime is 21198082693. The next prime is 21198082753. The reversal of 21198082729 is 92728089112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21198082729 - 2¹⁷ = 21197951657 is a prime.

It is a super-2 number, since 2×21198082729² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21198082429) 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, 17122227 + ... + 17123464.

It is an arithmetic number, because the mean of its divisors is an integer number (5308082260).

Almost surely, 2^21198082729 is an apocalyptic number.

It is an amenable number.

21198082729 is a deficient number, since it is larger than the sum of its proper divisors (34246311).

21198082729 is an equidigital number, since it uses as much as digits as its factorization.

21198082729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34246310.

The product of its (nonzero) digits is 290304, while the sum is 49.

The spelling of 21198082729 in words is "twenty-one billion, one hundred ninety-eight million, eighty-two thousand, seven hundred twenty-nine".