21345130709 has 4 divisors (see below), whose sum is σ = 24394435104. Its totient is φ = 18295826316.

The previous prime is 21345130679. The next prime is 21345130711. The reversal of 21345130709 is 90703154312.

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 a de Polignac number, because none of the positive numbers 2^k-21345130709 is a prime.

It is a super-2 number, since 2×21345130709² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21345130409) 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, 1524652187 + ... + 1524652200.

It is an arithmetic number, because the mean of its divisors is an integer number (6098608776).

Almost surely, 2^21345130709 is an apocalyptic number.

It is an amenable number.

21345130709 is a deficient number, since it is larger than the sum of its proper divisors (3049304395).

21345130709 is an equidigital number, since it uses as much as digits as its factorization.

21345130709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3049304394.

The product of its (nonzero) digits is 22680, while the sum is 35.

The spelling of 21345130709 in words is "twenty-one billion, three hundred forty-five million, one hundred thirty thousand, seven hundred nine".