21647104 has 18 divisors (see below), whose sum is σ = 43210160. Its totient is φ = 10823424.

The previous prime is 21647081. The next prime is 21647107. The reversal of 21647104 is 40174612.

It is a super-2 number, since 2×21647104² = 937194223173632, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21647107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42024 + ... + 42535.

Almost surely, 2^21647104 is an apocalyptic number.

It is an amenable number.

21647104 is a deficient number, since it is larger than the sum of its proper divisors (21563056).

21647104 is an frugal number, since it uses more digits than its factorization.

21647104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84575 (or 84561 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 21647104 is about 4652.6448392285. The cubic root of 21647104 is about 278.6976250744.

The spelling of 21647104 in words is "twenty-one million, six hundred forty-seven thousand, one hundred four".