66806261 has 16 divisors (see below), whose sum is σ = 72576000. Its totient is φ = 61286400.

The previous prime is 66806251. The next prime is 66806263. The reversal of 66806261 is 16260866.

It is not a de Polignac number, because 66806261 - 2⁶ = 66806197 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 (66806263) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 148565 + ... + 149013.

It is an arithmetic number, because the mean of its divisors is an integer number (4536000).

Almost surely, 2^66806261 is an apocalyptic number.

It is an amenable number.

66806261 is a deficient number, since it is larger than the sum of its proper divisors (5769739).

66806261 is a wasteful number, since it uses less digits than its factorization.

66806261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 700.

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 66806261 is about 8173.5097112562. The cubic root of 66806261 is about 405.7629493764.

The spelling of 66806261 in words is "sixty-six million, eight hundred six thousand, two hundred sixty-one".