61665211 has 4 divisors (see below), whose sum is σ = 61803000. Its totient is φ = 61527424.

The previous prime is 61665187. The next prime is 61665221. The reversal of 61665211 is 11256616.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 61665211 - 2⁵ = 61665179 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 61665211.

It is not an unprimeable number, because it can be changed into a prime (61665221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68221 + ... + 69118.

It is an arithmetic number, because the mean of its divisors is an integer number (15450750).

Almost surely, 2^61665211 is an apocalyptic number.

61665211 is a deficient number, since it is larger than the sum of its proper divisors (137789).

61665211 is a wasteful number, since it uses less digits than its factorization.

61665211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137788.

The product of its digits is 2160, while the sum is 28.

The square root of 61665211 is about 7852.7199746330. The cubic root of 61665211 is about 395.0754777520.

The spelling of 61665211 in words is "sixty-one million, six hundred sixty-five thousand, two hundred eleven".