61666563 has 8 divisors (see below), whose sum is σ = 93968128. Its totient is φ = 35238024.

The previous prime is 61666559. The next prime is 61666573. The reversal of 61666563 is 36566616.

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

It is not a de Polignac number, because 61666563 - 2² = 61666559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61666523) 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, 1468231 + ... + 1468272.

It is an arithmetic number, because the mean of its divisors is an integer number (11746016).

Almost surely, 2^61666563 is an apocalyptic number.

61666563 is a deficient number, since it is larger than the sum of its proper divisors (32301565).

61666563 is a wasteful number, since it uses less digits than its factorization.

61666563 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2936513.

The product of its digits is 116640, while the sum is 39.

The square root of 61666563 is about 7852.8060589830. The cubic root of 61666563 is about 395.0783650533.

The spelling of 61666563 in words is "sixty-one million, six hundred sixty-six thousand, five hundred sixty-three".