71805649 has 2 divisors, whose sum is σ = 71805650. Its totient is φ = 71805648.

The previous prime is 71805631. The next prime is 71805659. The reversal of 71805649 is 94650817.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70023424 + 1782225 = 8368^2 + 1335^2 .

It is a cyclic number.

It is not a de Polignac number, because 71805649 - 2⁷ = 71805521 is a prime.

It is a super-2 number, since 2×71805649² = 10312102456622402, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (71805659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35902824 + 35902825.

It is an arithmetic number, because the mean of its divisors is an integer number (35902825).

Almost surely, 2^71805649 is an apocalyptic number.

It is an amenable number.

71805649 is a deficient number, since it is larger than the sum of its proper divisors (1).

71805649 is an equidigital number, since it uses as much as digits as its factorization.

71805649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 71805649 is about 8473.8213929726. The cubic root of 71805649 is about 415.6421065867.

The spelling of 71805649 in words is "seventy-one million, eight hundred five thousand, six hundred forty-nine".