21020244121 has 8 divisors (see below), whose sum is σ = 22227545088. Its totient is φ = 19846020000.

The previous prime is 21020244109. The next prime is 21020244169. The reversal of 21020244121 is 12144202012.

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 21020244121 - 2¹⁵ = 21020211353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21020244181) 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 7 ways as a sum of consecutive naturals, for example, 8267905 + ... + 8270446.

It is an arithmetic number, because the mean of its divisors is an integer number (2778443136).

Almost surely, 2^21020244121 is an apocalyptic number.

It is an amenable number.

21020244121 is a deficient number, since it is larger than the sum of its proper divisors (1207300967).

21020244121 is a wasteful number, since it uses less digits than its factorization.

21020244121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16538423.

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21020244121 its reverse (12144202012), we get a palindrome (33164446133).

The spelling of 21020244121 in words is "twenty-one billion, twenty million, two hundred forty-four thousand, one hundred twenty-one".