66398220 has 72 divisors (see below), whose sum is σ = 230184864. Its totient is φ = 15176448.

The previous prime is 66398219. The next prime is 66398261. The reversal of 66398220 is 2289366.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25089 + ... + 27608.

It is an arithmetic number, because the mean of its divisors is an integer number (3197012).

Almost surely, 2^66398220 is an apocalyptic number.

66398220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66398220 is an abundant number, since it is smaller than the sum of its proper divisors (163786644).

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

66398220 is a wasteful number, since it uses less digits than its factorization.

66398220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52719 (or 52714 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 66398220 is about 8148.5102932990. The cubic root of 66398220 is about 404.9351519400.

The spelling of 66398220 in words is "sixty-six million, three hundred ninety-eight thousand, two hundred twenty".