66898440 has 128 divisors (see below), whose sum is σ = 254880000. Its totient is φ = 15289344.

The previous prime is 66898409. The next prime is 66898453. The reversal of 66898440 is 4489866.

It is a happy number.

66898440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3136 + ... + 11984.

It is an arithmetic number, because the mean of its divisors is an integer number (1991250).

Almost surely, 2^66898440 is an apocalyptic number.

66898440 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 66898440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127440000).

66898440 is an abundant number, since it is smaller than the sum of its proper divisors (187981560).

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

66898440 is a wasteful number, since it uses less digits than its factorization.

66898440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8876 (or 8866 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The square root of 66898440 is about 8179.1466547556. The cubic root of 66898440 is about 405.9494869493.

It can be divided in two parts, 6689 and 8440, that added together give a square (15129 = 123²).

The spelling of 66898440 in words is "sixty-six million, eight hundred ninety-eight thousand, four hundred forty".