66807814 has 4 divisors (see below), whose sum is σ = 100211724. Its totient is φ = 33403906.

The previous prime is 66807799. The next prime is 66807823. The reversal of 66807814 is 41870866.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 41870866 = 2 ⋅20935433.

It is a super-2 number, since 2×66807814² = 8926568022917192, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16701952 + ... + 16701955.

It is an arithmetic number, because the mean of its divisors is an integer number (25052931).

Almost surely, 2^66807814 is an apocalyptic number.

66807814 is a deficient number, since it is larger than the sum of its proper divisors (33403910).

66807814 is a wasteful number, since it uses less digits than its factorization.

66807814 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33403909.

The product of its (nonzero) digits is 64512, while the sum is 40.

The square root of 66807814 is about 8173.6047127323. The cubic root of 66807814 is about 405.7660935178.

The spelling of 66807814 in words is "sixty-six million, eight hundred seven thousand, eight hundred fourteen".