21201126500 has 48 divisors (see below), whose sum is σ = 46335984240. Its totient is φ = 8474457600.

The previous prime is 21201126481. The next prime is 21201126533. The reversal of 21201126500 is 562110212.

It can be written as a sum of positive squares in 8 ways, for example, as 10618478116 + 10582648384 = 103046^2 + 102872^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

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, 730262 + ... + 758738.

It is an arithmetic number, because the mean of its divisors is an integer number (965333005).

Almost surely, 2^21201126500 is an apocalyptic number.

21201126500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201126500 is an abundant number, since it is smaller than the sum of its proper divisors (25134857740).

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

21201126500 is a wasteful number, since it uses less digits than its factorization.

21201126500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29985 (or 29973 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21201126500 its reverse (562110212), we get a palindrome (21763236712).

The spelling of 21201126500 in words is "twenty-one billion, two hundred one million, one hundred twenty-six thousand, five hundred".