71664779 has 2 divisors, whose sum is σ = 71664780. Its totient is φ = 71664778.

The previous prime is 71664737. The next prime is 71664787. The reversal of 71664779 is 97746617.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71664779 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (71664709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35832389 + 35832390.

It is an arithmetic number, because the mean of its divisors is an integer number (35832390).

Almost surely, 2^71664779 is an apocalyptic number.

71664779 is a deficient number, since it is larger than the sum of its proper divisors (1).

71664779 is an equidigital number, since it uses as much as digits as its factorization.

71664779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 444528, while the sum is 47.

The square root of 71664779 is about 8465.5052418624. The cubic root of 71664779 is about 415.3701231824.

The spelling of 71664779 in words is "seventy-one million, six hundred sixty-four thousand, seven hundred seventy-nine".