66721446 has 24 divisors (see below), whose sum is σ = 157705704. Its totient is φ = 20218560.

The previous prime is 66721427. The next prime is 66721453. The reversal of 66721446 is 64412766.

It is a self number, because there is not a number n which added to its sum of digits gives 66721446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 168291 + ... + 168686.

It is an arithmetic number, because the mean of its divisors is an integer number (6571071).

Almost surely, 2^66721446 is an apocalyptic number.

66721446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

66721446 is an abundant number, since it is smaller than the sum of its proper divisors (90984258).

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

66721446 is a wasteful number, since it uses less digits than its factorization.

66721446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336996 (or 336993 counting only the distinct ones).

The product of its digits is 48384, while the sum is 36.

The square root of 66721446 is about 8168.3196558411. The cubic root of 66721446 is about 405.5911622901.

It can be divided in two parts, 6672 and 1446, that added together give a palindrome (8118).

The spelling of 66721446 in words is "sixty-six million, seven hundred twenty-one thousand, four hundred forty-six".