21354745 has 4 divisors (see below), whose sum is σ = 25625700. Its totient is φ = 17083792.

The previous prime is 21354721. The next prime is 21354797. The reversal of 21354745 is 54745312.

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 16386304 + 4968441 = 4048^2 + 2229^2 .

It is a cyclic number.

It is not a de Polignac number, because 21354745 - 2¹⁵ = 21321977 is a prime.

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, 2135470 + ... + 2135479.

It is an arithmetic number, because the mean of its divisors is an integer number (6406425).

Almost surely, 2^21354745 is an apocalyptic number.

It is an amenable number.

21354745 is a deficient number, since it is larger than the sum of its proper divisors (4270955).

21354745 is an equidigital number, since it uses as much as digits as its factorization.

21354745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4270954.

The product of its digits is 16800, while the sum is 31.

The square root of 21354745 is about 4621.1194531196. The cubic root of 21354745 is about 277.4372663428.

The spelling of 21354745 in words is "twenty-one million, three hundred fifty-four thousand, seven hundred forty-five".