66243905 has 64 divisors (see below), whose sum is σ = 103638528. Its totient is φ = 39536640.

The previous prime is 66243901. The next prime is 66243907. The reversal of 66243905 is 50934266.

It is not a de Polignac number, because 66243905 - 2² = 66243901 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66243901) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 988682 + ... + 988748.

It is an arithmetic number, because the mean of its divisors is an integer number (1619352).

Almost surely, 2^66243905 is an apocalyptic number.

66243905 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

66243905 is a deficient number, since it is larger than the sum of its proper divisors (37394623).

66243905 is a wasteful number, since it uses less digits than its factorization.

66243905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186.

The product of its (nonzero) digits is 38880, while the sum is 35.

The square root of 66243905 is about 8139.0358765643. The cubic root of 66243905 is about 404.6212075835.

The spelling of 66243905 in words is "sixty-six million, two hundred forty-three thousand, nine hundred five".