21079081 has 2 divisors, whose sum is σ = 21079082. Its totient is φ = 21079080.

The previous prime is 21079067. The next prime is 21079087. The reversal of 21079081 is 18097012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14402025 + 6677056 = 3795^2 + 2584^2 .

It is a cyclic number.

It is not a de Polignac number, because 21079081 - 2²¹ = 18981929 is a prime.

It is a super-3 number, since 3×21079081³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (21079087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10539540 + 10539541.

It is an arithmetic number, because the mean of its divisors is an integer number (10539541).

Almost surely, 2^21079081 is an apocalyptic number.

It is an amenable number.

21079081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21079081 is an equidigital number, since it uses as much as digits as its factorization.

21079081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 21079081 is about 4591.1960315369. The cubic root of 21079081 is about 276.2382988840.

The spelling of 21079081 in words is "twenty-one million, seventy-nine thousand, eighty-one".