71642561 has 2 divisors, whose sum is σ = 71642562. Its totient is φ = 71642560.

The previous prime is 71642537. The next prime is 71642567. The reversal of 71642561 is 16524617.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66994225 + 4648336 = 8185^2 + 2156^2 .

It is an emirp because it is prime and its reverse (16524617) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71642561 - 2²² = 67448257 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (71642567) 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, 35821280 + 35821281.

It is an arithmetic number, because the mean of its divisors is an integer number (35821281).

Almost surely, 2^71642561 is an apocalyptic number.

It is an amenable number.

71642561 is a deficient number, since it is larger than the sum of its proper divisors (1).

71642561 is an equidigital number, since it uses as much as digits as its factorization.

71642561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 32.

The square root of 71642561 is about 8464.1928735113. The cubic root of 71642561 is about 415.3271934597.

The spelling of 71642561 in words is "seventy-one million, six hundred forty-two thousand, five hundred sixty-one".