661380 has 48 divisors (see below), whose sum is σ = 1889664. Its totient is φ = 172800.

The previous prime is 661373. The next prime is 661393. The reversal of 661380 is 83166.

It is a self number, because there is not a number n which added to its sum of digits gives 661380.

It is an unprimeable number.

661380 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4305 + ... + 4455.

It is an arithmetic number, because the mean of its divisors is an integer number (39368).

2⁶⁶¹³⁸⁰ is an apocalyptic number.

661380 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 661380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (944832).

661380 is an abundant number, since it is smaller than the sum of its proper divisors (1228284).

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

661380 is a wasteful number, since it uses less digits than its factorization.

661380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236 (or 234 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 661380 is about 813.2527282463. The cubic root of 661380 is about 87.1265169449.

The spelling of 661380 in words is "six hundred sixty-one thousand, three hundred eighty".