21301345 has 16 divisors (see below), whose sum is σ = 28202832. Its totient is φ = 15344640.

The previous prime is 21301339. The next prime is 21301361. The reversal of 21301345 is 54310312.

It can be written as a sum of positive squares in 8 ways, for example, as 10751841 + 10549504 = 3279^2 + 3248^2 .

It is not a de Polignac number, because 21301345 - 2⁹ = 21300833 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1332 + ... + 6661.

It is an arithmetic number, because the mean of its divisors is an integer number (1762677).

Almost surely, 2^21301345 is an apocalyptic number.

21301345 is the 2665-th octagonal number.

It is an amenable number.

21301345 is a deficient number, since it is larger than the sum of its proper divisors (6901487).

21301345 is a wasteful number, since it uses less digits than its factorization.

21301345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8052.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21301345 is about 4615.3380157904. The cubic root of 21301345 is about 277.2058186996.

Adding to 21301345 its reverse (54310312), we get a palindrome (75611657).

The spelling of 21301345 in words is "twenty-one million, three hundred one thousand, three hundred forty-five".