1661572 has 18 divisors (see below), whose sum is σ = 3197054. Its totient is φ = 755040.

The previous prime is 1661567. The next prime is 1661587. The reversal of 1661572 is 2751661.

It can be written as a sum of positive squares in only one way, i.e., 1308736 + 352836 = 1144^2 + 594^2 .

It is a super-2 number, since 2×1661572² = 5521643022368, which contains 22 as substring.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 1661572.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1233 + ... + 2200.

2^1661572 is an apocalyptic number.

It is an amenable number.

1661572 is a deficient number, since it is larger than the sum of its proper divisors (1535482).

1661572 is a wasteful number, since it uses less digits than its factorization.

1661572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3459 (or 3446 counting only the distinct ones).

The product of its digits is 2520, while the sum is 28.

The square root of 1661572 is about 1289.0197826255. The cubic root of 1661572 is about 118.4421789400.

The spelling of 1661572 in words is "one million, six hundred sixty-one thousand, five hundred seventy-two".