21254807 has 4 divisors (see below), whose sum is σ = 24291216. Its totient is φ = 18218400.

The previous prime is 21254797. The next prime is 21254813. The reversal of 21254807 is 70845212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21254807 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21254807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21254867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1518194 + ... + 1518207.

It is an arithmetic number, because the mean of its divisors is an integer number (6072804).

Almost surely, 2^21254807 is an apocalyptic number.

21254807 is a deficient number, since it is larger than the sum of its proper divisors (3036409).

21254807 is an equidigital number, since it uses as much as digits as its factorization.

21254807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3036408.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 21254807 is about 4610.2935915189. The cubic root of 21254807 is about 277.0037968609.

The spelling of 21254807 in words is "twenty-one million, two hundred fifty-four thousand, eight hundred seven".