21018079 has 2 divisors, whose sum is σ = 21018080. Its totient is φ = 21018078.

The previous prime is 21018073. The next prime is 21018091. The reversal of 21018079 is 97081012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21018079 - 2⁷ = 21017951 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21018073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10509039 + 10509040.

It is an arithmetic number, because the mean of its divisors is an integer number (10509040).

Almost surely, 2^21018079 is an apocalyptic number.

21018079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21018079 is an equidigital number, since it uses as much as digits as its factorization.

21018079 is an evil number, because the sum of its binary digits is even.

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

The square root of 21018079 is about 4584.5478512063. The cubic root of 21018079 is about 275.9715672944.

It can be divided in two parts, 2 and 1018079, that added together give a square (1018081 = 1009²).

The spelling of 21018079 in words is "twenty-one million, eighteen thousand, seventy-nine".