21671304 has 16 divisors (see below), whose sum is σ = 54178320. Its totient is φ = 7223760.

The previous prime is 21671297. The next prime is 21671327. The reversal of 21671304 is 40317612.

It is a Harshad number since it is a multiple of its sum of digits (24), and also a Moran number because the ratio is a prime number: 902971 = 21671304 / (2 + 1 + 6 + 7 + 1 + 3 + 0 + 4).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 451462 + ... + 451509.

It is an arithmetic number, because the mean of its divisors is an integer number (3386145).

Almost surely, 2^21671304 is an apocalyptic number.

21671304 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21671304 is an abundant number, since it is smaller than the sum of its proper divisors (32507016).

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

21671304 is a wasteful number, since it uses less digits than its factorization.

21671304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 902980 (or 902976 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 21671304 is about 4655.2447841118. The cubic root of 21671304 is about 278.8014414370.

Adding to 21671304 its reverse (40317612), we get a palindrome (61988916).

The spelling of 21671304 in words is "twenty-one million, six hundred seventy-one thousand, three hundred four".