21436064 has 36 divisors (see below), whose sum is σ = 45649674. Its totient is φ = 9849984.

The previous prime is 21436027. The next prime is 21436067. The reversal of 21436064 is 46063412.

It can be written as a sum of positive squares in only one way, i.e., 20611600 + 824464 = 4540^2 + 908^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is not an unprimeable number, because it can be changed into a prime (21436067) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 94319 + ... + 94545.

Almost surely, 2^21436064 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 21436064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22824837).

21436064 is an abundant number, since it is smaller than the sum of its proper divisors (24213610).

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

21436064 is an equidigital number, since it uses as much as digits as its factorization.

21436064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477 (or 242 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 21436064 is about 4629.9097183422. The cubic root of 21436064 is about 277.7889812133.

Multiplying 21436064 by its sum of digits (26), we get a square (557337664 = 23608²).

21436064 divided by its sum of digits (26) gives a square (824464 = 908²).

Adding to 21436064 its reverse (46063412), we get a palindrome (67499476).

The spelling of 21436064 in words is "twenty-one million, four hundred thirty-six thousand, sixty-four".