661983 has 16 divisors (see below), whose sum is σ = 1044480. Its totient is φ = 364896.

The previous prime is 661961. The next prime is 661987. The reversal of 661983 is 389166.

It is not a de Polignac number, because 661983 - 2⁵ = 661951 is a prime.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661987) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66 + ... + 1152.

It is an arithmetic number, because the mean of its divisors is an integer number (65280).

2⁶⁶¹⁹⁸³ is an apocalyptic number.

661983 is a deficient number, since it is larger than the sum of its proper divisors (382497).

661983 is a wasteful number, since it uses less digits than its factorization.

661983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1126.

The product of its digits is 7776, while the sum is 33.

The square root of 661983 is about 813.6233772453. The cubic root of 661983 is about 87.1529875222.

The spelling of 661983 in words is "six hundred sixty-one thousand, nine hundred eighty-three".