21163136 has 32 divisors (see below), whose sum is σ = 42604380. Its totient is φ = 10470400.

The previous prime is 21163133. The next prime is 21163139. The reversal of 21163136 is 63136112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21163133) and next prime (21163139).

It can be written as a sum of positive squares in 2 ways, for example, as 21160000 + 3136 = 4600^2 + 56^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (21163133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12110 + ... + 13746.

Almost surely, 2^21163136 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 21163136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21302190).

21163136 is an abundant number, since it is smaller than the sum of its proper divisors (21441244).

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

21163136 is a wasteful number, since it uses less digits than its factorization.

21163136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1752 (or 1740 counting only the distinct ones).

The product of its digits is 648, while the sum is 23.

The square root of 21163136 is about 4600.3408569366. The cubic root of 21163136 is about 276.6049881055.

Adding to 21163136 its reverse (63136112), we get a palindrome (84299248).

It can be divided in two parts, 2116 and 3136, that multiplied together give a square (6635776 = 2576²).

The spelling of 21163136 in words is "twenty-one million, one hundred sixty-three thousand, one hundred thirty-six".