66870421 has 2 divisors, whose sum is σ = 66870422. Its totient is φ = 66870420.

The previous prime is 66870403. The next prime is 66870431. The reversal of 66870421 is 12407866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65691025 + 1179396 = 8105^2 + 1086^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66870421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66870431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33435210 + 33435211.

It is an arithmetic number, because the mean of its divisors is an integer number (33435211).

Almost surely, 2^66870421 is an apocalyptic number.

It is an amenable number.

66870421 is a deficient number, since it is larger than the sum of its proper divisors (1).

66870421 is an equidigital number, since it uses as much as digits as its factorization.

66870421 is an evil number, because the sum of its binary digits is even.

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

The square root of 66870421 is about 8177.4336438763. The cubic root of 66870421 is about 405.8928045762.

The spelling of 66870421 in words is "sixty-six million, eight hundred seventy thousand, four hundred twenty-one".