61666599 has 16 divisors (see below), whose sum is σ = 88363008. Its totient is φ = 38113152.

The previous prime is 61666589. The next prime is 61666639. The reversal of 61666599 is 99566616.

It is not a de Polignac number, because 61666599 - 2¹⁶ = 61601063 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61666529) 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, 5607 + ... + 12440.

It is an arithmetic number, because the mean of its divisors is an integer number (5522688).

Almost surely, 2^61666599 is an apocalyptic number.

61666599 is a deficient number, since it is larger than the sum of its proper divisors (26696409).

61666599 is a wasteful number, since it uses less digits than its factorization.

61666599 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18134.

The product of its digits is 524880, while the sum is 48.

The square root of 61666599 is about 7852.8083511569. The cubic root of 61666599 is about 395.0784419336.

The spelling of 61666599 in words is "sixty-one million, six hundred sixty-six thousand, five hundred ninety-nine".