21404693 has 4 divisors (see below), whose sum is σ = 21860160. Its totient is φ = 20949228.

The previous prime is 21404689. The next prime is 21404729. The reversal of 21404693 is 39640412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21404693 - 2² = 21404689 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21404623) 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, 227663 + ... + 227756.

It is an arithmetic number, because the mean of its divisors is an integer number (5465040).

Almost surely, 2^21404693 is an apocalyptic number.

It is an amenable number.

21404693 is a deficient number, since it is larger than the sum of its proper divisors (455467).

21404693 is an equidigital number, since it uses as much as digits as its factorization.

21404693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455466.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 21404693 is about 4626.5206148898. The cubic root of 21404693 is about 277.6534032650.

The spelling of 21404693 in words is "twenty-one million, four hundred four thousand, six hundred ninety-three".