66923220 has 288 divisors, whose sum is σ = 250967808. Its totient is φ = 13160448.

The previous prime is 66923209. The next prime is 66923249. The reversal of 66923220 is 2232966.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 649689 + ... + 649791.

It is an arithmetic number, because the mean of its divisors is an integer number (871416).

Almost surely, 2^66923220 is an apocalyptic number.

66923220 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 66923220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125483904).

66923220 is an abundant number, since it is smaller than the sum of its proper divisors (184044588).

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

66923220 is a wasteful number, since it uses less digits than its factorization.

66923220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 30.

The square root of 66923220 is about 8180.6613424588. The cubic root of 66923220 is about 405.9996036461. Note that the first 3 decimals are identical.

The spelling of 66923220 in words is "sixty-six million, nine hundred twenty-three thousand, two hundred twenty".