1661634 has 48 divisors (see below), whose sum is σ = 4036032. Its totient is φ = 509328.

The previous prime is 1661629. The next prime is 1661641. The reversal of 1661634 is 4361661.

1661634 is a `hidden beast` number, since 16 + 616 + 34 = 666.

It is a super-2 number, since 2×1661634² = 5522055099912, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 1661598 and 1661607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6187 + ... + 6449.

It is an arithmetic number, because the mean of its divisors is an integer number (84084).

2^1661634 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1661634, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2018016).

1661634 is an abundant number, since it is smaller than the sum of its proper divisors (2374398).

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

1661634 is a wasteful number, since it uses less digits than its factorization.

1661634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293 (or 281 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 1661634 is about 1289.0438316830. The cubic root of 1661634 is about 118.4436521079.

Adding to 1661634 its sum of digits (27), we get a palindrome (1661661).

The spelling of 1661634 in words is "one million, six hundred sixty-one thousand, six hundred thirty-four".