21011142500 has 60 divisors (see below), whose sum is σ = 46114560492. Its totient is φ = 8373840000.

The previous prime is 21011142487. The next prime is 21011142511. The reversal of 21011142500 is 524111012.

It can be written as a sum of positive squares in 10 ways, for example, as 20608899364 + 402243136 = 143558^2 + 20056^2 .

It is a congruent number.

It is an unprimeable number.

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 19 ways as a sum of consecutive naturals, for example, 677330 + ... + 707670.

Almost surely, 2^21011142500 is an apocalyptic number.

21011142500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21011142500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23057280246).

21011142500 is an abundant number, since it is smaller than the sum of its proper divisors (25103417992).

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

21011142500 is a wasteful number, since it uses less digits than its factorization.

21011142500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30642 (or 30625 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 17.

Adding to 21011142500 its reverse (524111012), we get a palindrome (21535253512).

The spelling of 21011142500 in words is "twenty-one billion, eleven million, one hundred forty-two thousand, five hundred".