66816997 has 8 divisors (see below), whose sum is σ = 74278400. Its totient is φ = 59687280.

The previous prime is 66816983. The next prime is 66817007. The reversal of 66816997 is 79961866.

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 66816997 - 2¹¹ = 66814949 is a prime.

It is a super-2 number, since 2×66816997² = 8929022176196018, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66816907) 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, 82497 + ... + 83302.

It is an arithmetic number, because the mean of its divisors is an integer number (9284800).

Almost surely, 2^66816997 is an apocalyptic number.

It is an amenable number.

66816997 is a deficient number, since it is larger than the sum of its proper divisors (7461403).

66816997 is a wasteful number, since it uses less digits than its factorization.

66816997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165843.

The product of its digits is 979776, while the sum is 52.

The square root of 66816997 is about 8174.1664406837. The cubic root of 66816997 is about 405.7846840543.

The spelling of 66816997 in words is "sixty-six million, eight hundred sixteen thousand, nine hundred ninety-seven".