66669857 has 2 divisors, whose sum is σ = 66669858. Its totient is φ = 66669856.

The previous prime is 66669851. The next prime is 66669899. The reversal of 66669857 is 75896666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37466641 + 29203216 = 6121^2 + 5404^2 .

It is a cyclic number.

It is not a de Polignac number, because 66669857 - 2¹² = 66665761 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 66669799 and 66669808.

It is not a weakly prime, because it can be changed into another prime (66669851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33334928 + 33334929.

It is an arithmetic number, because the mean of its divisors is an integer number (33334929).

Almost surely, 2^66669857 is an apocalyptic number.

It is an amenable number.

66669857 is a deficient number, since it is larger than the sum of its proper divisors (1).

66669857 is an equidigital number, since it uses as much as digits as its factorization.

66669857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3265920, while the sum is 53.

The square root of 66669857 is about 8165.1611741594. The cubic root of 66669857 is about 405.4866010190.

The spelling of 66669857 in words is "sixty-six million, six hundred sixty-nine thousand, eight hundred fifty-seven".