21320136 has 48 divisors (see below), whose sum is σ = 58004700. Its totient is φ = 7074432.

The previous prime is 21320107. The next prime is 21320183. The reversal of 21320136 is 63102312.

It can be written as a sum of positive squares in 2 ways, for example, as 20520900 + 799236 = 4530^2 + 894^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19410 + ... + 20478.

Almost surely, 2^21320136 is an apocalyptic number.

It is an amenable number.

21320136 is an abundant number, since it is smaller than the sum of its proper divisors (36684564).

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

21320136 is a wasteful number, since it uses less digits than its factorization.

21320136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1358 (or 1351 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21320136 is about 4617.3732792574. The cubic root of 21320136 is about 277.2873071939.

Adding to 21320136 its reverse (63102312), we get a palindrome (84422448).

The spelling of 21320136 in words is "twenty-one million, three hundred twenty thousand, one hundred thirty-six".