61661666 has 32 divisors (see below), whose sum is σ = 108711936. Its totient is φ = 25938000.

The previous prime is 61661653. The next prime is 61661681. The reversal of 61661666 is 66616616.

It is a super-2 number, since 2×61661666² = 7604322107791112, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13721 + ... + 17651.

It is an arithmetic number, because the mean of its divisors is an integer number (3397248).

Almost surely, 2^61661666 is an apocalyptic number.

61661666 is a deficient number, since it is larger than the sum of its proper divisors (47050270).

61661666 is a wasteful number, since it uses less digits than its factorization.

61661666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3998.

The product of its digits is 46656, while the sum is 38.

The square root of 61661666 is about 7852.4942534204. The cubic root of 61661666 is about 395.0679069278.

The spelling of 61661666 in words is "sixty-one million, six hundred sixty-one thousand, six hundred sixty-six".