61666500 has 144 divisors (see below), whose sum is σ = 209139840. Its totient is φ = 14078400.

The previous prime is 61666487. The next prime is 61666523. The reversal of 61666500 is 566616.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 73081 + ... + 73919.

It is an arithmetic number, because the mean of its divisors is an integer number (1452360).

Almost surely, 2^61666500 is an apocalyptic number.

61666500 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 61666500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104569920).

61666500 is an abundant number, since it is smaller than the sum of its proper divisors (147473340).

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

61666500 is a wasteful number, since it uses less digits than its factorization.

61666500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 875 (or 856 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 61666500 is about 7852.8020476770. The cubic root of 61666500 is about 395.0782305129.

The spelling of 61666500 in words is "sixty-one million, six hundred sixty-six thousand, five hundred".