1661916 has 12 divisors (see below), whose sum is σ = 3877832. Its totient is φ = 553968.

The previous prime is 1661899. The next prime is 1661917. The reversal of 1661916 is 6191661.

1661916 = 115² + 116² + ... + 186².

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69235 + ... + 69258.

2^1661916 is an apocalyptic number.

It is an amenable number.

1661916 is an abundant number, since it is smaller than the sum of its proper divisors (2215916).

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

1661916 is a wasteful number, since it uses less digits than its factorization.

1661916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138500 (or 138498 counting only the distinct ones).

The product of its digits is 1944, while the sum is 30.

The square root of 1661916 is about 1289.1532104447. The cubic root of 1661916 is about 118.4503521836.

The spelling of 1661916 in words is "one million, six hundred sixty-one thousand, nine hundred sixteen".