21309814949 has 8 divisors (see below), whose sum is σ = 21356160000. Its totient is φ = 21263506992.

The previous prime is 21309814937. The next prime is 21309814961. The reversal of 21309814949 is 94941890312.

It is an interprime number because it is at equal distance from previous prime (21309814937) and next prime (21309814961).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21309814949 - 2⁸ = 21309814693 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21309814897 and 21309814906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21309814909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1351292 + ... + 1366970.

It is an arithmetic number, because the mean of its divisors is an integer number (2669520000).

Almost surely, 2^21309814949 is an apocalyptic number.

It is an amenable number.

21309814949 is a deficient number, since it is larger than the sum of its proper divisors (46345051).

21309814949 is a wasteful number, since it uses less digits than its factorization.

21309814949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18547.

The product of its (nonzero) digits is 559872, while the sum is 50.

The spelling of 21309814949 in words is "twenty-one billion, three hundred nine million, eight hundred fourteen thousand, nine hundred forty-nine".