21349205 has 4 divisors (see below), whose sum is σ = 25619052. Its totient is φ = 17079360.

The previous prime is 21349193. The next prime is 21349213. The reversal of 21349205 is 50294312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14070001 + 7279204 = 3751^2 + 2698^2 .

It is not a de Polignac number, because 21349205 - 2⁴ = 21349189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2134916 + ... + 2134925.

It is an arithmetic number, because the mean of its divisors is an integer number (6404763).

Almost surely, 2^21349205 is an apocalyptic number.

It is an amenable number.

21349205 is a deficient number, since it is larger than the sum of its proper divisors (4269847).

21349205 is an equidigital number, since it uses as much as digits as its factorization.

21349205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4269846.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 21349205 is about 4620.5199923818. The cubic root of 21349205 is about 277.4132726841.

The spelling of 21349205 in words is "twenty-one million, three hundred forty-nine thousand, two hundred five".