1661716 has 24 divisors (see below), whose sum is σ = 3519936. Its totient is φ = 670080.

The previous prime is 1661713. The next prime is 1661731. The reversal of 1661716 is 6171661.

1661716 = 144² + 145² + ... + 199².

It is a super-2 number, since 2×1661716² = 5522600129312, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661713) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1270 + ... + 2221.

It is an arithmetic number, because the mean of its divisors is an integer number (146664).

2^1661716 is an apocalyptic number.

It is an amenable number.

1661716 is an abundant number, since it is smaller than the sum of its proper divisors (1858220).

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

1661716 is a wasteful number, since it uses less digits than its factorization.

1661716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3519 (or 3517 counting only the distinct ones).

The product of its digits is 1512, while the sum is 28.

The square root of 1661716 is about 1289.0756378118. The cubic root of 1661716 is about 118.4456004350.

The spelling of 1661716 in words is "one million, six hundred sixty-one thousand, seven hundred sixteen".