21300405 has 32 divisors (see below), whose sum is σ = 41243904. Its totient is φ = 9163776.

The previous prime is 21300403. The next prime is 21300421. The reversal of 21300405 is 50400312.

It is not a de Polignac number, because 21300405 - 2¹ = 21300403 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 not an unprimeable number, because it can be changed into a prime (21300401) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4182 + ... + 7751.

It is an arithmetic number, because the mean of its divisors is an integer number (1288872).

Almost surely, 2^21300405 is an apocalyptic number.

It is an amenable number.

21300405 is a deficient number, since it is larger than the sum of its proper divisors (19943499).

21300405 is a wasteful number, since it uses less digits than its factorization.

21300405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11965.

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

The square root of 21300405 is about 4615.2361803054. The cubic root of 21300405 is about 277.2017410650.

Adding to 21300405 its reverse (50400312), we get a palindrome (71700717).

The spelling of 21300405 in words is "twenty-one million, three hundred thousand, four hundred five".