21947220049 has 4 divisors (see below), whose sum is σ = 21993039360. Its totient is φ = 21901400740.

The previous prime is 21947220047. The next prime is 21947220089. The reversal of 21947220049 is 94002274912.

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 21947220049 - 2¹ = 21947220047 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21947219993 and 21947220020.

It is not an unprimeable number, because it can be changed into a prime (21947220041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22908937 + ... + 22909894.

It is an arithmetic number, because the mean of its divisors is an integer number (5498259840).

Almost surely, 2^21947220049 is an apocalyptic number.

It is an amenable number.

21947220049 is a deficient number, since it is larger than the sum of its proper divisors (45819311).

21947220049 is an equidigital number, since it uses as much as digits as its factorization.

21947220049 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45819310.

The product of its (nonzero) digits is 72576, while the sum is 40.

The spelling of 21947220049 in words is "twenty-one billion, nine hundred forty-seven million, two hundred twenty thousand, forty-nine".