75666421 has 2 divisors, whose sum is σ = 75666422. Its totient is φ = 75666420.

The previous prime is 75666419. The next prime is 75666427. The reversal of 75666421 is 12466657.

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., 50566321 + 25100100 = 7111^2 + 5010^2 .

It is a cyclic number.

It is not a de Polignac number, because 75666421 - 2¹ = 75666419 is a prime.

Together with 75666419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (75666427) 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, 37833210 + 37833211.

It is an arithmetic number, because the mean of its divisors is an integer number (37833211).

Almost surely, 2^75666421 is an apocalyptic number.

It is an amenable number.

75666421 is a deficient number, since it is larger than the sum of its proper divisors (1).

75666421 is an equidigital number, since it uses as much as digits as its factorization.

75666421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 37.

The square root of 75666421 is about 8698.6447795044. The cubic root of 75666421 is about 422.9617206463.

The spelling of 75666421 in words is "seventy-five million, six hundred sixty-six thousand, four hundred twenty-one".