21094081 has 2 divisors, whose sum is σ = 21094082. Its totient is φ = 21094080.

The previous prime is 21094069. The next prime is 21094097. The reversal of 21094081 is 18049012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14250625 + 6843456 = 3775^2 + 2616^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21094081 is a prime.

It is a super-2 number, since 2×21094081² = 889920506469122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21094001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10547040 + 10547041.

It is an arithmetic number, because the mean of its divisors is an integer number (10547041).

Almost surely, 2^21094081 is an apocalyptic number.

It is an amenable number.

21094081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21094081 is an equidigital number, since it uses as much as digits as its factorization.

21094081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 21094081 is about 4592.8293022929. The cubic root of 21094081 is about 276.3038076224.

The spelling of 21094081 in words is "twenty-one million, ninety-four thousand, eighty-one".