66691700 has 36 divisors (see below), whose sum is σ = 145076652. Its totient is φ = 26611200.

The previous prime is 66691699. The next prime is 66691711. The reversal of 66691700 is 719666.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 4376464 + 62315236 = 2092^2 + 7894^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 75260 + ... + 76140.

It is an arithmetic number, because the mean of its divisors is an integer number (4029907).

Almost surely, 2^66691700 is an apocalyptic number.

It is an amenable number.

66691700 is an abundant number, since it is smaller than the sum of its proper divisors (78384952).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66691700 is a wasteful number, since it uses less digits than its factorization.

66691700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1652 (or 1645 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 35.

The square root of 66691700 is about 8166.4986377272. The cubic root of 66691700 is about 405.5308792837.

The spelling of 66691700 in words is "sixty-six million, six hundred ninety-one thousand, seven hundred".