66687890 has 8 divisors (see below), whose sum is σ = 120038220. Its totient is φ = 26675152.

The previous prime is 66687871. The next prime is 66687893. The reversal of 66687890 is 9878666.

It can be written as a sum of positive squares in 2 ways, for example, as 65302561 + 1385329 = 8081^2 + 1177^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (66687893) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3334385 + ... + 3334404.

Almost surely, 2^66687890 is an apocalyptic number.

66687890 is a deficient number, since it is larger than the sum of its proper divisors (53350330).

66687890 is a wasteful number, since it uses less digits than its factorization.

66687890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6668796.

The product of its (nonzero) digits is 870912, while the sum is 50.

The square root of 66687890 is about 8166.2653642898. The cubic root of 66687890 is about 405.5231566731.

The spelling of 66687890 in words is "sixty-six million, six hundred eighty-seven thousand, eight hundred ninety".