66220440 has 256 divisors, whose sum is σ = 248209920. Its totient is φ = 13885440.

The previous prime is 66220403. The next prime is 66220459. The reversal of 66220440 is 4402266.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 66220440.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 291607 + ... + 291833.

It is an arithmetic number, because the mean of its divisors is an integer number (969570).

Almost surely, 2^66220440 is an apocalyptic number.

66220440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66220440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124104960).

66220440 is an abundant number, since it is smaller than the sum of its proper divisors (181989480).

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

66220440 is a wasteful number, since it uses less digits than its factorization.

66220440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282 (or 278 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 66220440 is about 8137.5942390857. The cubic root of 66220440 is about 404.5734267957.

The spelling of 66220440 in words is "sixty-six million, two hundred twenty thousand, four hundred forty".