2181647663309 has 4 divisors (see below), whose sum is σ = 2181658566240. Its totient is φ = 2181636760380.

The previous prime is 2181647663269. The next prime is 2181647663323. The reversal of 2181647663309 is 9033667461812.

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 2181647663309 - 2⁸ = 2181647663053 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 (2181647663399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5145599 + ... + 5553420.

It is an arithmetic number, because the mean of its divisors is an integer number (545414641560).

Almost surely, 2^{2181647663309} is an apocalyptic number.

It is an amenable number.

2181647663309 is a deficient number, since it is larger than the sum of its proper divisors (10902931).

2181647663309 is a wasteful number, since it uses less digits than its factorization.

2181647663309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10902930.

The product of its (nonzero) digits is 7838208, while the sum is 56.

The spelling of 2181647663309 in words is "two trillion, one hundred eighty-one billion, six hundred forty-seven million, six hundred sixty-three thousand, three hundred nine".