66821416 has 16 divisors (see below), whose sum is σ = 125992800. Its totient is φ = 33223344.

The previous prime is 66821401. The next prime is 66821429. The reversal of 66821416 is 61412866.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21900 + ... + 24763.

It is an arithmetic number, because the mean of its divisors is an integer number (7874550).

Almost surely, 2^66821416 is an apocalyptic number.

It is an amenable number.

66821416 is a deficient number, since it is larger than the sum of its proper divisors (59171384).

66821416 is a wasteful number, since it uses less digits than its factorization.

66821416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46848 (or 46844 counting only the distinct ones).

The product of its digits is 13824, while the sum is 34.

The square root of 66821416 is about 8174.4367390053. The cubic root of 66821416 is about 405.7936294977.

The spelling of 66821416 in words is "sixty-six million, eight hundred twenty-one thousand, four hundred sixteen".