66723381 has 24 divisors (see below), whose sum is σ = 98055360. Its totient is φ = 43716096.

The previous prime is 66723379. The next prime is 66723407. The reversal of 66723381 is 18332766.

It is a happy number.

It is not a de Polignac number, because 66723381 - 2¹ = 66723379 is a prime.

It is a super-2 number, since 2×66723381² = 8904019144142322, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66723301) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 185680 + ... + 186038.

It is an arithmetic number, because the mean of its divisors is an integer number (4085640).

Almost surely, 2^66723381 is an apocalyptic number.

It is an amenable number.

66723381 is a deficient number, since it is larger than the sum of its proper divisors (31331979).

66723381 is a wasteful number, since it uses less digits than its factorization.

66723381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 665 (or 662 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 66723381 is about 8168.4381003959. The cubic root of 66723381 is about 405.5950831249.

The spelling of 66723381 in words is "sixty-six million, seven hundred twenty-three thousand, three hundred eighty-one".