21996198 has 120 divisors (see below), whose sum is σ = 61079832. Its totient is φ = 5878656.

The previous prime is 21996197. The next prime is 21996199. The reversal of 21996198 is 89169912.

21996198 is a `hidden beast` number, since 21 + 9 + 9 + 619 + 8 = 666.

It is an interprime number because it is at equal distance from previous prime (21996197) and next prime (21996199).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21996197) 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 59 ways as a sum of consecutive naturals, for example, 134865 + ... + 135027.

Almost surely, 2^21996198 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21996198, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30539916).

21996198 is an abundant number, since it is smaller than the sum of its proper divisors (39083634).

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

21996198 is a wasteful number, since it uses less digits than its factorization.

21996198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208 (or 192 counting only the distinct ones).

The product of its digits is 69984, while the sum is 45.

The square root of 21996198 is about 4690.0104477496. The cubic root of 21996198 is about 280.1877906909.

The spelling of 21996198 in words is "twenty-one million, nine hundred ninety-six thousand, one hundred ninety-eight".