66021814 has 4 divisors (see below), whose sum is σ = 99032724. Its totient is φ = 33010906.

The previous prime is 66021779. The next prime is 66021853. The reversal of 66021814 is 41812066.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 41812066 = 2 ⋅20906033.

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, 16505452 + ... + 16505455.

It is an arithmetic number, because the mean of its divisors is an integer number (24758181).

Almost surely, 2^66021814 is an apocalyptic number.

66021814 is a deficient number, since it is larger than the sum of its proper divisors (33010910).

66021814 is a wasteful number, since it uses less digits than its factorization.

66021814 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33010909.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 66021814 is about 8125.3808526124. The cubic root of 66021814 is about 404.1685201932.

The spelling of 66021814 in words is "sixty-six million, twenty-one thousand, eight hundred fourteen".