79621709 has 2 divisors, whose sum is σ = 79621710. Its totient is φ = 79621708.

The previous prime is 79621679. The next prime is 79621747. The reversal of 79621709 is 90712697.

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., 78234025 + 1387684 = 8845^2 + 1178^2 .

It is a cyclic number.

It is not a de Polignac number, because 79621709 - 2⁸ = 79621453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79621109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39810854 + 39810855.

It is an arithmetic number, because the mean of its divisors is an integer number (39810855).

Almost surely, 2^79621709 is an apocalyptic number.

It is an amenable number.

79621709 is a deficient number, since it is larger than the sum of its proper divisors (1).

79621709 is an equidigital number, since it uses as much as digits as its factorization.

79621709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 47628, while the sum is 41.

The square root of 79621709 is about 8923.0997416817. The cubic root of 79621709 is about 430.2066952922.

The spelling of 79621709 in words is "seventy-nine million, six hundred twenty-one thousand, seven hundred nine".