71605421 has 2 divisors, whose sum is σ = 71605422. Its totient is φ = 71605420.

The previous prime is 71605351. The next prime is 71605441. The reversal of 71605421 is 12450617.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71588521 + 16900 = 8461^2 + 130^2 .

It is an emirp because it is prime and its reverse (12450617) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71605421 - 2²² = 67411117 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71605441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35802710 + 35802711.

It is an arithmetic number, because the mean of its divisors is an integer number (35802711).

Almost surely, 2^71605421 is an apocalyptic number.

It is an amenable number.

71605421 is a deficient number, since it is larger than the sum of its proper divisors (1).

71605421 is an equidigital number, since it uses as much as digits as its factorization.

71605421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 71605421 is about 8461.9986409831. The cubic root of 71605421 is about 415.2554115560.

The spelling of 71605421 in words is "seventy-one million, six hundred five thousand, four hundred twenty-one".