21971136 has 112 divisors (see below), whose sum is σ = 64666368. Its totient is φ = 6528000.

The previous prime is 21971129. The next prime is 21971143. The reversal of 21971136 is 63117912.

It is an interprime number because it is at equal distance from previous prime (21971129) and next prime (21971143).

It is a super-3 number, since 3×21971136³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 213261 + ... + 213363.

Almost surely, 2^21971136 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 21971136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32333184).

21971136 is an abundant number, since it is smaller than the sum of its proper divisors (42695232).

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

21971136 is a wasteful number, since it uses less digits than its factorization.

21971136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230 (or 220 counting only the distinct ones).

The product of its digits is 2268, while the sum is 30.

The square root of 21971136 is about 4687.3378371950. The cubic root of 21971136 is about 280.0813369145.

It can be divided in two parts, 2197 and 1136, that added together give a palindrome (3333).

The spelling of 21971136 in words is "twenty-one million, nine hundred seventy-one thousand, one hundred thirty-six".