661950 has 36 divisors (see below), whose sum is σ = 1779648. Its totient is φ = 176400.

The previous prime is 661949. The next prime is 661951. The reversal of 661950 is 59166.

It is an interprime number because it is at equal distance from previous prime (661949) and next prime (661951).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 286 + ... + 1185.

2⁶⁶¹⁹⁵⁰ is an apocalyptic number.

661950 is an abundant number, since it is smaller than the sum of its proper divisors (1117698).

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

661950 is a wasteful number, since it uses less digits than its factorization.

661950 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1489 (or 1481 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 661950 is about 813.6030973392. The cubic root of 661950 is about 87.1515392995.

It can be divided in two parts, 66 and 1950, that added together give a triangular number (2016 = T₆₃).

The spelling of 661950 in words is "six hundred sixty-one thousand, nine hundred fifty".