21098636 has 54 divisors (see below), whose sum is σ = 42503580. Its totient is φ = 9156576.

The previous prime is 21098633. The next prime is 21098639. The reversal of 21098636 is 63689012.

It is an interprime number because it is at equal distance from previous prime (21098633) and next prime (21098639).

It is a junction number, because it is equal to n+sod(n) for n = 21098596 and 21098605.

It is not an unprimeable number, because it can be changed into a prime (21098633) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 357575 + ... + 357633.

Almost surely, 2^21098636 is an apocalyptic number.

21098636 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21098636 is an abundant number, since it is smaller than the sum of its proper divisors (21404944).

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

21098636 is a wasteful number, since it uses less digits than its factorization.

21098636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 21098636 is about 4593.3251572254. The cubic root of 21098636 is about 276.3236942952.

The spelling of 21098636 in words is "twenty-one million, ninety-eight thousand, six hundred thirty-six".