21403005 has 24 divisors (see below), whose sum is σ = 37086048. Its totient is φ = 10535616.

The previous prime is 21402977. The next prime is 21403013. The reversal of 21403005 is 50030412.

It is not a de Polignac number, because 21403005 - 2⁷ = 21402877 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1687 + ... + 6756.

It is an arithmetic number, because the mean of its divisors is an integer number (1545252).

Almost surely, 2^21403005 is an apocalyptic number.

It is an amenable number.

21403005 is a deficient number, since it is larger than the sum of its proper divisors (15683043).

21403005 is a wasteful number, since it uses less digits than its factorization.

21403005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8477 (or 8464 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 15.

The square root of 21403005 is about 4626.3381847850. The cubic root of 21403005 is about 277.6461043787.

Adding to 21403005 its reverse (50030412), we get a palindrome (71433417).

The spelling of 21403005 in words is "twenty-one million, four hundred three thousand, five".