21840242099 has 4 divisors (see below), whose sum is σ = 23520260736. Its totient is φ = 20160223464.

The previous prime is 21840242093. The next prime is 21840242107. The reversal of 21840242099 is 99024204812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21840242099 - 2¹² = 21840238003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21840242093) 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 3 ways as a sum of consecutive naturals, for example, 840009299 + ... + 840009324.

It is an arithmetic number, because the mean of its divisors is an integer number (5880065184).

Almost surely, 2^21840242099 is an apocalyptic number.

21840242099 is a deficient number, since it is larger than the sum of its proper divisors (1680018637).

21840242099 is a wasteful number, since it uses less digits than its factorization.

21840242099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1680018636.

The product of its (nonzero) digits is 82944, while the sum is 41.

The spelling of 21840242099 in words is "twenty-one billion, eight hundred forty million, two hundred forty-two thousand, ninety-nine".