66810901 has 8 divisors (see below), whose sum is σ = 71135064. Its totient is φ = 62530560.

The previous prime is 66810889. The next prime is 66810943. The reversal of 66810901 is 10901866.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 372100 + 66438801 = 610^2 + 8151^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 66810901 - 2¹¹ = 66808853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66810701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7780 + ... + 13933.

It is an arithmetic number, because the mean of its divisors is an integer number (8891883).

Almost surely, 2^66810901 is an apocalyptic number.

It is an amenable number.

66810901 is a deficient number, since it is larger than the sum of its proper divisors (4324163).

66810901 is a wasteful number, since it uses less digits than its factorization.

66810901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21911.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 66810901 is about 8173.7935501210. The cubic root of 66810901 is about 405.7723431891.

The spelling of 66810901 in words is "sixty-six million, eight hundred ten thousand, nine hundred one".