21533121050 has 72 divisors (see below), whose sum is σ = 46785247740. Its totient is φ = 7351948800.

The previous prime is 21533121037. The next prime is 21533121121. The reversal of 21533121050 is 5012133512.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 8836564009 + 12696557041 = 94003^2 + 112679^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 572216 + ... + 608684.

Almost surely, 2^21533121050 is an apocalyptic number.

21533121050 is an abundant number, since it is smaller than the sum of its proper divisors (25252126690).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21533121050 is a wasteful number, since it uses less digits than its factorization.

21533121050 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36736 (or 36724 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 23.

Adding to 21533121050 its reverse (5012133512), we get a palindrome (26545254562).

The spelling of 21533121050 in words is "twenty-one billion, five hundred thirty-three million, one hundred twenty-one thousand, fifty".