21297569999 has 4 divisors (see below), whose sum is σ = 21340251000. Its totient is φ = 21254889000.

The previous prime is 21297569977. The next prime is 21297570013. The reversal of 21297569999 is 99996579212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21297569999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21297569099) 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, 21339752 + ... + 21340749.

It is an arithmetic number, because the mean of its divisors is an integer number (5335062750).

Almost surely, 2^21297569999 is an apocalyptic number.

21297569999 is a deficient number, since it is larger than the sum of its proper divisors (42681001).

21297569999 is an equidigital number, since it uses as much as digits as its factorization.

21297569999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42681000.

The product of its digits is 49601160, while the sum is 68.

The spelling of 21297569999 in words is "twenty-one billion, two hundred ninety-seven million, five hundred sixty-nine thousand, nine hundred ninety-nine".