661750 has 16 divisors (see below), whose sum is σ = 1239264. Its totient is φ = 264600.

The previous prime is 661741. The next prime is 661769. The reversal of 661750 is 57166.

661750 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

661750 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 7 ways as a sum of consecutive naturals, for example, 1074 + ... + 1573.

It is an arithmetic number, because the mean of its divisors is an integer number (77454).

2⁶⁶¹⁷⁵⁰ is an apocalyptic number.

661750 is a deficient number, since it is larger than the sum of its proper divisors (577514).

661750 is a wasteful number, since it uses less digits than its factorization.

661750 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2664 (or 2654 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 661750 is about 813.4801780007. The cubic root of 661750 is about 87.1427611624.

The spelling of 661750 in words is "six hundred sixty-one thousand, seven hundred fifty".