71999999 has 2 divisors, whose sum is σ = 72000000. Its totient is φ = 71999998.

The previous prime is 71999989. The next prime is 72000007. The reversal of 71999999 is 99999917.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71999999 is a prime.

71999999 is a modest number, since divided by 9999 gives 7199 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71999909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35999999 + 36000000.

It is an arithmetic number, because the mean of its divisors is an integer number (36000000).

Almost surely, 2^71999999 is an apocalyptic number.

71999999 is a deficient number, since it is larger than the sum of its proper divisors (1).

71999999 is an equidigital number, since it uses as much as digits as its factorization.

71999999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3720087, while the sum is 62.

The square root of 71999999 is about 8485.2813153130. The cubic root of 71999999 is about 416.0167626844.

The spelling of 71999999 in words is "seventy-one million, nine hundred ninety-nine thousand, nine hundred ninety-nine".