66621437 has 2 divisors, whose sum is σ = 66621438. Its totient is φ = 66621436.

The previous prime is 66621421. The next prime is 66621509. The reversal of 66621437 is 73412666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 33570436 + 33051001 = 5794^2 + 5749^2 .

It is a cyclic number.

It is not a de Polignac number, because 66621437 - 2⁴ = 66621421 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 66621397 and 66621406.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66621407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33310718 + 33310719.

It is an arithmetic number, because the mean of its divisors is an integer number (33310719).

Almost surely, 2^66621437 is an apocalyptic number.

It is an amenable number.

66621437 is a deficient number, since it is larger than the sum of its proper divisors (1).

66621437 is an equidigital number, since it uses as much as digits as its factorization.

66621437 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 35.

The square root of 66621437 is about 8162.1955992245. The cubic root of 66621437 is about 405.3884136366.

The spelling of 66621437 in words is "sixty-six million, six hundred twenty-one thousand, four hundred thirty-seven".