21254745 has 16 divisors (see below), whose sum is σ = 34516800. Its totient is φ = 11166144.

The previous prime is 21254729. The next prime is 21254789. The reversal of 21254745 is 54745212.

It is not a de Polignac number, because 21254745 - 2⁴ = 21254729 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon 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, 9570 + ... + 11579.

It is an arithmetic number, because the mean of its divisors is an integer number (2157300).

Almost surely, 2^21254745 is an apocalyptic number.

It is an amenable number.

21254745 is a deficient number, since it is larger than the sum of its proper divisors (13262055).

21254745 is a wasteful number, since it uses less digits than its factorization.

21254745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21224.

The product of its digits is 11200, while the sum is 30.

The square root of 21254745 is about 4610.2868674303. The cubic root of 21254745 is about 277.0035275218.

Adding to 21254745 its reverse (54745212), we get a palindrome (75999957).

The spelling of 21254745 in words is "twenty-one million, two hundred fifty-four thousand, seven hundred forty-five".