21222720121 has 8 divisors (see below), whose sum is σ = 21529800000. Its totient is φ = 20915867280.

The previous prime is 21222720119. The next prime is 21222720137. The reversal of 21222720121 is 12102722212.

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

It is not a de Polignac number, because 21222720121 - 2¹ = 21222720119 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222720092 and 21222720101.

It is not an unprimeable number, because it can be changed into a prime (21222720721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 136255 + ... + 247003.

It is an arithmetic number, because the mean of its divisors is an integer number (2691225000).

Almost surely, 2^21222720121 is an apocalyptic number.

It is an amenable number.

21222720121 is a deficient number, since it is larger than the sum of its proper divisors (307079879).

21222720121 is a wasteful number, since it uses less digits than its factorization.

21222720121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113519.

The product of its (nonzero) digits is 448, while the sum is 22.

The spelling of 21222720121 in words is "twenty-one billion, two hundred twenty-two million, seven hundred twenty thousand, one hundred twenty-one".