21053044121 has 4 divisors (see below), whose sum is σ = 21566533044. Its totient is φ = 20539555200.

The previous prime is 21053044109. The next prime is 21053044139. The reversal of 21053044121 is 12144035012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8433667225 + 12619376896 = 91835^2 + 112336^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21053044121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21053044151) 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, 256744400 + ... + 256744481.

It is an arithmetic number, because the mean of its divisors is an integer number (5391633261).

Almost surely, 2^21053044121 is an apocalyptic number.

It is an amenable number.

21053044121 is a deficient number, since it is larger than the sum of its proper divisors (513488923).

21053044121 is an equidigital number, since it uses as much as digits as its factorization.

21053044121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513488922.

The product of its (nonzero) digits is 960, while the sum is 23.

Adding to 21053044121 its reverse (12144035012), we get a palindrome (33197079133).

The spelling of 21053044121 in words is "twenty-one billion, fifty-three million, forty-four thousand, one hundred twenty-one".