21021432100 has 18 divisors (see below), whose sum is σ = 45616507874. Its totient is φ = 8408572800.

The previous prime is 21021432073. The next prime is 21021432109. The reversal of 21021432100 is 123412012.

It can be written as a sum of positive squares in 3 ways, for example, as 320553216 + 20700878884 = 17904^2 + 143878^2 .

It is not an unprimeable number, because it can be changed into a prime (21021432109) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 105107061 + ... + 105107260.

Almost surely, 2^21021432100 is an apocalyptic number.

21021432100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021432100 is an abundant number, since it is smaller than the sum of its proper divisors (24595075774).

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

21021432100 is a wasteful number, since it uses less digits than its factorization.

21021432100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210214335 (or 210214328 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21021432100 its reverse (123412012), we get a palindrome (21144844112).

The spelling of 21021432100 in words is "twenty-one billion, twenty-one million, four hundred thirty-two thousand, one hundred".