21445016500 has 24 divisors (see below), whose sum is σ = 46835917128. Its totient is φ = 8578006400.

The previous prime is 21445016473. The next prime is 21445016531. The reversal of 21445016500 is 561054412.

It can be written as a sum of positive squares in 4 ways, for example, as 1882518544 + 19562497956 = 43388^2 + 139866^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21444517 + ... + 21445516.

It is an arithmetic number, because the mean of its divisors is an integer number (1951496547).

Almost surely, 2^21445016500 is an apocalyptic number.

21445016500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21445016500 is an abundant number, since it is smaller than the sum of its proper divisors (25390900628).

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

21445016500 is a wasteful number, since it uses less digits than its factorization.

21445016500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42890052 (or 42890040 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 28.

The spelling of 21445016500 in words is "twenty-one billion, four hundred forty-five million, sixteen thousand, five hundred".