16561100243 has 8 divisors (see below), whose sum is σ = 16957414656. Its totient is φ = 16169315400.

The previous prime is 16561100197. The next prime is 16561100249. The reversal of 16561100243 is 34200116561.

It is a happy number.

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 16561100243 - 2¹⁴ = 16561083859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16561100249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1124993 + ... + 1139618.

It is an arithmetic number, because the mean of its divisors is an integer number (2119676832).

Almost surely, 2^16561100243 is an apocalyptic number.

16561100243 is a deficient number, since it is larger than the sum of its proper divisors (396314413).

16561100243 is a wasteful number, since it uses less digits than its factorization.

16561100243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2264785.

The product of its (nonzero) digits is 4320, while the sum is 29.

The spelling of 16561100243 in words is "sixteen billion, five hundred sixty-one million, one hundred thousand, two hundred forty-three".