21121102051 has 16 divisors (see below), whose sum is σ = 24644664000. Its totient is φ = 18093776064.

The previous prime is 21121102049. The next prime is 21121102091. The reversal of 21121102051 is 15020112112.

It is not a de Polignac number, because 21121102051 - 2¹ = 21121102049 is a prime.

It is a super-2 number, since 2×21121102051² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121102091) 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 15 ways as a sum of consecutive naturals, for example, 640065 + ... + 672253.

It is an arithmetic number, because the mean of its divisors is an integer number (1540291500).

Almost surely, 2^21121102051 is an apocalyptic number.

21121102051 is a deficient number, since it is larger than the sum of its proper divisors (3523561949).

21121102051 is an equidigital number, since it uses as much as digits as its factorization.

21121102051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34123 (or 34109 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 16.

Adding to 21121102051 its reverse (15020112112), we get a palindrome (36141214163).

The spelling of 21121102051 in words is "twenty-one billion, one hundred twenty-one million, one hundred two thousand, fifty-one".