16221020500 has 24 divisors (see below), whose sum is σ = 35426709864. Its totient is φ = 6488408000.

The previous prime is 16221020479. The next prime is 16221020507. The reversal of 16221020500 is 502012261.

It can be written as a sum of positive squares in 4 ways, for example, as 5035536 + 16215984964 = 2244^2 + 127342^2 .

It is a super-2 number, since 2×16221020500² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16221020507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16220521 + ... + 16221520.

It is an arithmetic number, because the mean of its divisors is an integer number (1476112911).

Almost surely, 2^16221020500 is an apocalyptic number.

16221020500 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16221020500 is an abundant number, since it is smaller than the sum of its proper divisors (19205689364).

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

16221020500 is a wasteful number, since it uses less digits than its factorization.

16221020500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32442060 (or 32442048 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

Adding to 16221020500 its reverse (502012261), we get a palindrome (16723032761).

It can be divided in two parts, 162210 and 20500, that added together give a triangular number (182710 = T₆₀₄).

The spelling of 16221020500 in words is "sixteen billion, two hundred twenty-one million, twenty thousand, five hundred".