66781420 has 24 divisors (see below), whose sum is σ = 146339424. Its totient is φ = 25550976.

The previous prime is 66781391. The next prime is 66781453. The reversal of 66781420 is 2418766.

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, 72129 + ... + 73048.

It is an arithmetic number, because the mean of its divisors is an integer number (6097476).

Almost surely, 2^66781420 is an apocalyptic number.

It is an amenable number.

66781420 is an abundant number, since it is smaller than the sum of its proper divisors (79558004).

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

66781420 is a wasteful number, since it uses less digits than its factorization.

66781420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145209 (or 145207 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 66781420 is about 8171.9899657305. The cubic root of 66781420 is about 405.7126506627.

The spelling of 66781420 in words is "sixty-six million, seven hundred eighty-one thousand, four hundred twenty".