1661636 has 6 divisors (see below), whose sum is σ = 2907870. Its totient is φ = 830816.

The previous prime is 1661629. The next prime is 1661641. The reversal of 1661636 is 6361661.

It can be written as a sum of positive squares in only one way, i.e., 1577536 + 84100 = 1256^2 + 290^2 .

It is a super-2 number, since 2×1661636² = 5522068392992, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1661599 and 1661608.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 207701 + ... + 207708.

It is an arithmetic number, because the mean of its divisors is an integer number (484645).

2^1661636 is an apocalyptic number.

It is an amenable number.

1661636 is a deficient number, since it is larger than the sum of its proper divisors (1246234).

1661636 is a wasteful number, since it uses less digits than its factorization.

1661636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415413 (or 415411 counting only the distinct ones).

The product of its digits is 3888, while the sum is 29.

The square root of 1661636 is about 1289.0446074516. The cubic root of 1661636 is about 118.4436996288.

The spelling of 1661636 in words is "one million, six hundred sixty-one thousand, six hundred thirty-six".