21131136 has 192 divisors, whose sum is σ = 70171920. Its totient is φ = 6045696.

The previous prime is 21131087. The next prime is 21131137. The reversal of 21131136 is 63113112.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131137) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 254551 + ... + 254633.

Almost surely, 2^21131136 is an apocalyptic number.

21131136 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21131136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35085960).

21131136 is an abundant number, since it is smaller than the sum of its proper divisors (49040784).

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

21131136 is a wasteful number, since it uses less digits than its factorization.

21131136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133 (or 118 counting only the distinct ones).

The product of its digits is 108, while the sum is 18.

The square root of 21131136 is about 4596.8615380496. The cubic root of 21131136 is about 276.4655030336.

Adding to 21131136 its reverse (63113112), we get a palindrome (84244248).

It can be divided in two parts, 2113 and 1136, that added together give a square (3249 = 57²).

The spelling of 21131136 in words is "twenty-one million, one hundred thirty-one thousand, one hundred thirty-six".