71651989 has 2 divisors, whose sum is σ = 71651990. Its totient is φ = 71651988.

The previous prime is 71651981. The next prime is 71651999. The reversal of 71651989 is 98915617.

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., 55249489 + 16402500 = 7433^2 + 4050^2 .

It is a cyclic number.

It is not a de Polignac number, because 71651989 - 2³ = 71651981 is a prime.

It is a super-2 number, since 2×71651989² = 10268015055312242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71651981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35825994 + 35825995.

It is an arithmetic number, because the mean of its divisors is an integer number (35825995).

Almost surely, 2^71651989 is an apocalyptic number.

It is an amenable number.

71651989 is a deficient number, since it is larger than the sum of its proper divisors (1).

71651989 is an equidigital number, since it uses as much as digits as its factorization.

71651989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 46.

The square root of 71651989 is about 8464.7497895685. The cubic root of 71651989 is about 415.3454113690.

The spelling of 71651989 in words is "seventy-one million, six hundred fifty-one thousand, nine hundred eighty-nine".