21454164 has 18 divisors (see below), whose sum is σ = 54231450. Its totient is φ = 7151376.

The previous prime is 21454163. The next prime is 21454217. The reversal of 21454164 is 46145412.

It can be written as a sum of positive squares in only one way, i.e., 17994564 + 3459600 = 4242^2 + 1860^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21454163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 297939 + ... + 298010.

Almost surely, 2^21454164 is an apocalyptic number.

It is an amenable number.

21454164 is an abundant number, since it is smaller than the sum of its proper divisors (32777286).

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

21454164 is a wasteful number, since it uses less digits than its factorization.

21454164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 595959 (or 595954 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 21454164 is about 4631.8639876404. The cubic root of 21454164 is about 277.8671449108.

Adding to 21454164 its reverse (46145412), we get a palindrome (67599576).

The spelling of 21454164 in words is "twenty-one million, four hundred fifty-four thousand, one hundred sixty-four".