61666111 has 8 divisors (see below), whose sum is σ = 66531024. Its totient is φ = 56818560.

The previous prime is 61666103. The next prime is 61666117. The reversal of 61666111 is 11166616.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61666111 - 2³ = 61666103 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 61666111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61666117) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3591 + ... + 11671.

It is an arithmetic number, because the mean of its divisors is an integer number (8316378).

Almost surely, 2^61666111 is an apocalyptic number.

61666111 is a deficient number, since it is larger than the sum of its proper divisors (4864913).

61666111 is a wasteful number, since it uses less digits than its factorization.

61666111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8681.

The product of its digits is 1296, while the sum is 28.

The square root of 61666111 is about 7852.7772794089. Note that the first 3 decimals coincide. The cubic root of 61666111 is about 395.0773997768.

The spelling of 61666111 in words is "sixty-one million, six hundred sixty-six thousand, one hundred eleven".