66087421 has 4 divisors (see below), whose sum is σ = 66371292. Its totient is φ = 65803552.

The previous prime is 66087419. The next prime is 66087457. The reversal of 66087421 is 12478066.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12478066 = 2 ⋅6239033.

It can be written as a sum of positive squares in 2 ways, for example, as 23328900 + 42758521 = 4830^2 + 6539^2 .

It is a cyclic number.

It is not a de Polignac number, because 66087421 - 2¹ = 66087419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66087221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141586 + ... + 142051.

It is an arithmetic number, because the mean of its divisors is an integer number (16592823).

Almost surely, 2^66087421 is an apocalyptic number.

It is an amenable number.

66087421 is a deficient number, since it is larger than the sum of its proper divisors (283871).

66087421 is a wasteful number, since it uses less digits than its factorization.

66087421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283870.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 66087421 is about 8129.4170147680. The cubic root of 66087421 is about 404.3023522512.

The spelling of 66087421 in words is "sixty-six million, eighty-seven thousand, four hundred twenty-one".