79666421 has 2 divisors, whose sum is σ = 79666422. Its totient is φ = 79666420.

The previous prime is 79666409. The next prime is 79666441. The reversal of 79666421 is 12466697.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79459396 + 207025 = 8914^2 + 455^2 .

It is an emirp because it is prime and its reverse (12466697) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 79666421 - 2⁶ = 79666357 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79666441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39833210 + 39833211.

It is an arithmetic number, because the mean of its divisors is an integer number (39833211).

Almost surely, 2^79666421 is an apocalyptic number.

It is an amenable number.

79666421 is a deficient number, since it is larger than the sum of its proper divisors (1).

79666421 is an equidigital number, since it uses as much as digits as its factorization.

79666421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 41.

The square root of 79666421 is about 8925.6047974353. The cubic root of 79666421 is about 430.2872085196.

The spelling of 79666421 in words is "seventy-nine million, six hundred sixty-six thousand, four hundred twenty-one".