21416004 has 18 divisors (see below), whose sum is σ = 54134990. Its totient is φ = 7138656.

The previous prime is 21415991. The next prime is 21416023. The reversal of 21416004 is 40061412.

Added to its reverse (40061412) it gives a triangular number (61477416 = T₁₁₀₈₈).

21416004 is a `hidden beast` number, since 21 + 41 + 600 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19342404 + 2073600 = 4398^2 + 1440^2 .

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

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

It is a plaindrome in base 13.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 297409 + ... + 297480.

Almost surely, 2^21416004 is an apocalyptic number.

It is an amenable number.

21416004 is an abundant number, since it is smaller than the sum of its proper divisors (32718986).

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

21416004 is a wasteful number, since it uses less digits than its factorization.

21416004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594899 (or 594894 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21416004 is about 4627.7428623466. The cubic root of 21416004 is about 277.7023019593.

Adding to 21416004 its reverse (40061412), we get a palindrome (61477416).

It can be divided in two parts, 21 and 416004, that added together give a square (416025 = 645²).

The spelling of 21416004 in words is "twenty-one million, four hundred sixteen thousand, four".