66666437 has 2 divisors, whose sum is σ = 66666438. Its totient is φ = 66666436.

The previous prime is 66666433. The next prime is 66666487. The reversal of 66666437 is 73466666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66601921 + 64516 = 8161^2 + 254^2 .

It is a cyclic number.

It is not a de Polignac number, because 66666437 - 2² = 66666433 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66666433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33333218 + 33333219.

It is an arithmetic number, because the mean of its divisors is an integer number (33333219).

Almost surely, 2^66666437 is an apocalyptic number.

It is an amenable number.

66666437 is a deficient number, since it is larger than the sum of its proper divisors (1).

66666437 is an equidigital number, since it uses as much as digits as its factorization.

66666437 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 44.

The square root of 66666437 is about 8164.9517451115. The cubic root of 66666437 is about 405.4796674113.

The spelling of 66666437 in words is "sixty-six million, six hundred sixty-six thousand, four hundred thirty-seven".