666061620 has 96 divisors (see below), whose sum is σ = 2167603200. Its totient is φ = 149656704.

The previous prime is 666061619. The next prime is 666061633. The reversal of 666061620 is 26160666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11341 + ... + 38219.

It is an arithmetic number, because the mean of its divisors is an integer number (22579200).

Almost surely, 2^666061620 is an apocalyptic number.

666061620 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 666061620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1083801600).

666061620 is an abundant number, since it is smaller than the sum of its proper divisors (1501541580).

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

666061620 is a wasteful number, since it uses less digits than its factorization.

666061620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26957 (or 26955 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 33.

The square root of 666061620 is about 25808.1696367642. The cubic root of 666061620 is about 873.3161062714.

The spelling of 666061620 in words is "six hundred sixty-six million, sixty-one thousand, six hundred twenty".