66818420 has 24 divisors (see below), whose sum is σ = 140588448. Its totient is φ = 26676000.

The previous prime is 66818413. The next prime is 66818461. The reversal of 66818420 is 2481866.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8495 + ... + 14345.

It is an arithmetic number, because the mean of its divisors is an integer number (5857852).

Almost surely, 2^66818420 is an apocalyptic number.

It is an amenable number.

66818420 is an abundant number, since it is smaller than the sum of its proper divisors (73770028).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66818420 is a wasteful number, since it uses less digits than its factorization.

66818420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6431 (or 6429 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 35.

The square root of 66818420 is about 8174.2534827347. The cubic root of 66818420 is about 405.7875646961.

The spelling of 66818420 in words is "sixty-six million, eight hundred eighteen thousand, four hundred twenty".