21404963 has 4 divisors (see below), whose sum is σ = 22531560. Its totient is φ = 20278368.

The previous prime is 21404941. The next prime is 21404983. The reversal of 21404963 is 36940412.

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

It is a cyclic number.

It is not a de Polignac number, because 21404963 - 2⁶ = 21404899 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21404923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 563270 + ... + 563307.

It is an arithmetic number, because the mean of its divisors is an integer number (5632890).

Almost surely, 2^21404963 is an apocalyptic number.

21404963 is a deficient number, since it is larger than the sum of its proper divisors (1126597).

21404963 is a wasteful number, since it uses less digits than its factorization.

21404963 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1126596.

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

The square root of 21404963 is about 4626.5497943932. The cubic root of 21404963 is about 277.6545707053.

The spelling of 21404963 in words is "twenty-one million, four hundred four thousand, nine hundred sixty-three".