71971819 has 2 divisors, whose sum is σ = 71971820. Its totient is φ = 71971818.

The previous prime is 71971811. The next prime is 71971831. The reversal of 71971819 is 91817917.

It is a weak prime.

It is an emirp because it is prime and its reverse (91817917) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71971819 - 2³ = 71971811 is a prime.

It is a super-2 number, since 2×71971819² = 10359885460337522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (71971811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35985909 + 35985910.

It is an arithmetic number, because the mean of its divisors is an integer number (35985910).

Almost surely, 2^71971819 is an apocalyptic number.

71971819 is a deficient number, since it is larger than the sum of its proper divisors (1).

71971819 is an equidigital number, since it uses as much as digits as its factorization.

71971819 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31752, while the sum is 43.

The square root of 71971819 is about 8483.6206303677. The cubic root of 71971819 is about 415.9624808217.

The spelling of 71971819 in words is "seventy-one million, nine hundred seventy-one thousand, eight hundred nineteen".