66420840 has 32 divisors (see below), whose sum is σ = 199262880. Its totient is φ = 17712192.

The previous prime is 66420829. The next prime is 66420857. The reversal of 66420840 is 4802466.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 66420798 and 66420807.

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, 276634 + ... + 276873.

It is an arithmetic number, because the mean of its divisors is an integer number (6226965).

Almost surely, 2^66420840 is an apocalyptic number.

66420840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66420840 is an abundant number, since it is smaller than the sum of its proper divisors (132842040).

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

66420840 is a wasteful number, since it uses less digits than its factorization.

66420840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 553521 (or 553517 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 66420840 is about 8149.8981588729. The cubic root of 66420840 is about 404.9811300460.

The spelling of 66420840 in words is "sixty-six million, four hundred twenty thousand, eight hundred forty".