21198756 has 48 divisors (see below), whose sum is σ = 52606400. Its totient is φ = 6625152.

The previous prime is 21198731. The next prime is 21198757. The reversal of 21198756 is 65789112.

It is not an unprimeable number, because it can be changed into a prime (21198757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24426 + ... + 25278.

Almost surely, 2^21198756 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21198756, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26303200).

21198756 is an abundant number, since it is smaller than the sum of its proper divisors (31407644).

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

21198756 is a wasteful number, since it uses less digits than its factorization.

21198756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 988 (or 986 counting only the distinct ones).

The product of its digits is 30240, while the sum is 39.

The square root of 21198756 is about 4604.2106815392. The cubic root of 21198756 is about 276.7600871594.

The spelling of 21198756 in words is "twenty-one million, one hundred ninety-eight thousand, seven hundred fifty-six".