21404707 has 4 divisors (see below), whose sum is σ = 21573376. Its totient is φ = 21236040.

The previous prime is 21404689. The next prime is 21404729. The reversal of 21404707 is 70740412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21404707 is a prime.

It is a super-2 number, since 2×21404707² = 916322963511698, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21474707) by changing a digit.

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, 84144 + ... + 84397.

It is an arithmetic number, because the mean of its divisors is an integer number (5393344).

Almost surely, 2^21404707 is an apocalyptic number.

21404707 is a deficient number, since it is larger than the sum of its proper divisors (168669).

21404707 is a wasteful number, since it uses less digits than its factorization.

21404707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168668.

The product of its (nonzero) digits is 1568, while the sum is 25.

The square root of 21404707 is about 4626.5221279056. The cubic root of 21404707 is about 277.6534637992.

The spelling of 21404707 in words is "twenty-one million, four hundred four thousand, seven hundred seven".