21353487689 has 4 divisors (see below), whose sum is σ = 21372848256. Its totient is φ = 21334127124.

The previous prime is 21353487647. The next prime is 21353487703. The reversal of 21353487689 is 98678435312.

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-21353487689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21353481689) 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, 9678629 + ... + 9680834.

It is an arithmetic number, because the mean of its divisors is an integer number (5343212064).

Almost surely, 2^21353487689 is an apocalyptic number.

It is an amenable number.

21353487689 is a deficient number, since it is larger than the sum of its proper divisors (19360567).

21353487689 is a wasteful number, since it uses less digits than its factorization.

21353487689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19360566.

The product of its digits is 8709120, while the sum is 56.

The spelling of 21353487689 in words is "twenty-one billion, three hundred fifty-three million, four hundred eighty-seven thousand, six hundred eighty-nine".