21403073 has 8 divisors (see below), whose sum is σ = 22212480. Its totient is φ = 20598480.

The previous prime is 21403061. The next prime is 21403079. The reversal of 21403073 is 37030412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21403073 - 2⁸ = 21402817 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21403079) 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 7 ways as a sum of consecutive naturals, for example, 9638 + ... + 11648.

It is an arithmetic number, because the mean of its divisors is an integer number (2776560).

Almost surely, 2^21403073 is an apocalyptic number.

It is an amenable number.

21403073 is a deficient number, since it is larger than the sum of its proper divisors (809407).

21403073 is a wasteful number, since it uses less digits than its factorization.

21403073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2407.

The product of its (nonzero) digits is 504, while the sum is 20.

The square root of 21403073 is about 4626.3455340041. The cubic root of 21403073 is about 277.6463984171.

Adding to 21403073 its reverse (37030412), we get a palindrome (58433485).

The spelling of 21403073 in words is "twenty-one million, four hundred three thousand, seventy-three".