66781373 has 4 divisors (see below), whose sum is σ = 66815808. Its totient is φ = 66746940.

The previous prime is 66781369. The next prime is 66781381. The reversal of 66781373 is 37318766.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66781373 - 2² = 66781369 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66781373.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66781873) 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, 14123 + ... + 18248.

It is an arithmetic number, because the mean of its divisors is an integer number (16703952).

Almost surely, 2^66781373 is an apocalyptic number.

It is an amenable number.

66781373 is a deficient number, since it is larger than the sum of its proper divisors (34435).

66781373 is a wasteful number, since it uses less digits than its factorization.

66781373 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34434.

The product of its digits is 127008, while the sum is 41.

The square root of 66781373 is about 8171.9870900534. The cubic root of 66781373 is about 405.7125554840.

The spelling of 66781373 in words is "sixty-six million, seven hundred eighty-one thousand, three hundred seventy-three".