66023640 has 128 divisors (see below), whose sum is σ = 222436800. Its totient is φ = 17418240.

The previous prime is 66023621. The next prime is 66023647. The reversal of 66023640 is 4632066.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66023647) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 121770 + ... + 122310.

Almost surely, 2^66023640 is an apocalyptic number.

66023640 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 66023640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111218400).

66023640 is an abundant number, since it is smaller than the sum of its proper divisors (156413160).

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

66023640 is a wasteful number, since it uses less digits than its factorization.

66023640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 674 (or 664 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 66023640 is about 8125.4932157993. The cubic root of 66023640 is about 404.1722462592.

The spelling of 66023640 in words is "sixty-six million, twenty-three thousand, six hundred forty".