21216415531500 has 144 divisors (see below), whose sum is σ = 76492250243136. Its totient is φ = 4849466400000.

The previous prime is 21216415531481. The next prime is 21216415531511. The reversal of 21216415531500 is 513551461212.

21216415531500 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 64 + 15 + 531 + 50 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 336737001 + ... + 336800000.

It is an arithmetic number, because the mean of its divisors is an integer number (531196182244).

Almost surely, 2^{21216415531500} is an apocalyptic number.

21216415531500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21216415531500 is an abundant number, since it is smaller than the sum of its proper divisors (55275834711636).

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

21216415531500 is a wasteful number, since it uses less digits than its factorization.

21216415531500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 673537033 (or 673537018 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

Adding to 21216415531500 its reverse (513551461212), we get a palindrome (21729966992712).

The spelling of 21216415531500 in words is "twenty-one trillion, two hundred sixteen billion, four hundred fifteen million, five hundred thirty-one thousand, five hundred".