21533121051 has 32 divisors (see below), whose sum is σ = 31799496960. Its totient is φ = 12877087104.

The previous prime is 21533121037. The next prime is 21533121121. The reversal of 21533121051 is 15012133512.

It is not a de Polignac number, because 21533121051 - 2²² = 21528926747 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21533121751) 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 31 ways as a sum of consecutive naturals, for example, 297780 + ... + 362958.

It is an arithmetic number, because the mean of its divisors is an integer number (993734280).

Almost surely, 2^21533121051 is an apocalyptic number.

21533121051 is a deficient number, since it is larger than the sum of its proper divisors (10266375909).

21533121051 is a wasteful number, since it uses less digits than its factorization.

21533121051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65435.

The product of its (nonzero) digits is 900, while the sum is 24.

Adding to 21533121051 its reverse (15012133512), we get a palindrome (36545254563).

The spelling of 21533121051 in words is "twenty-one billion, five hundred thirty-three million, one hundred twenty-one thousand, fifty-one".