66861731 has 8 divisors (see below), whose sum is σ = 70943040. Its totient is φ = 62796928.

The previous prime is 66861727. The next prime is 66861737. The reversal of 66861731 is 13716866.

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 66861731 - 2² = 66861727 is a prime.

It is a super-2 number, since 2×66861731² = 8940982144632722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (66861737) 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, 4790 + ... + 12516.

It is an arithmetic number, because the mean of its divisors is an integer number (8867880).

Almost surely, 2^66861731 is an apocalyptic number.

66861731 is a deficient number, since it is larger than the sum of its proper divisors (4081309).

66861731 is a wasteful number, since it uses less digits than its factorization.

66861731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8253.

The product of its digits is 36288, while the sum is 38.

The square root of 66861731 is about 8176.9022863185. The cubic root of 66861731 is about 405.8752215092.

The spelling of 66861731 in words is "sixty-six million, eight hundred sixty-one thousand, seven hundred thirty-one".