21456011 has 4 divisors (see below), whose sum is σ = 21955032. Its totient is φ = 20956992.

The previous prime is 21456007. The next prime is 21456047. The reversal of 21456011 is 11065412.

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

It is a cyclic number.

It is not a de Polignac number, because 21456011 - 2² = 21456007 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21456311) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 249446 + ... + 249531.

It is an arithmetic number, because the mean of its divisors is an integer number (5488758).

Almost surely, 2^21456011 is an apocalyptic number.

21456011 is a deficient number, since it is larger than the sum of its proper divisors (499021).

21456011 is an equidigital number, since it uses as much as digits as its factorization.

21456011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 499020.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 21456011 is about 4632.0633631245. The cubic root of 21456011 is about 277.8751185904.

The spelling of 21456011 in words is "twenty-one million, four hundred fifty-six thousand, eleven".