21440801 has 2 divisors, whose sum is σ = 21440802. Its totient is φ = 21440800.

The previous prime is 21440719. The next prime is 21440803. The reversal of 21440801 is 10804412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21390625 + 50176 = 4625^2 + 224^2 .

It is a cyclic number.

It is not a de Polignac number, because 21440801 - 2²² = 17246497 is a prime.

Together with 21440803, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21440803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10720400 + 10720401.

It is an arithmetic number, because the mean of its divisors is an integer number (10720401).

Almost surely, 2^21440801 is an apocalyptic number.

It is an amenable number.

21440801 is a deficient number, since it is larger than the sum of its proper divisors (1).

21440801 is an equidigital number, since it uses as much as digits as its factorization.

21440801 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 21440801 is about 4630.4212551344. The cubic root of 21440801 is about 277.8094418956.

The spelling of 21440801 in words is "twenty-one million, four hundred forty thousand, eight hundred one".