21405914 has 4 divisors (see below), whose sum is σ = 32108874. Its totient is φ = 10702956.

The previous prime is 21405899. The next prime is 21405931. The reversal of 21405914 is 41950412.

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

It can be written as a sum of positive squares in only one way, i.e., 13082689 + 8323225 = 3617^2 + 2885^2 .

It is a Curzon number.

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 as a sum of consecutive naturals, namely, 5351477 + ... + 5351480.

Almost surely, 2^21405914 is an apocalyptic number.

21405914 is a deficient number, since it is larger than the sum of its proper divisors (10702960).

21405914 is a wasteful number, since it uses less digits than its factorization.

21405914 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10702959.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 21405914 is about 4626.6525696231. The cubic root of 21405914 is about 277.6586826113.

The spelling of 21405914 in words is "twenty-one million, four hundred five thousand, nine hundred fourteen".