1661205441 has 16 divisors (see below), whose sum is σ = 2538882944. Its totient is φ = 946439424.

The previous prime is 1661205407. The next prime is 1661205451. The reversal of 1661205441 is 1445021661.

It is not a de Polignac number, because 1661205441 - 2¹⁹ = 1660681153 is a prime.

It is a super-3 number, since 3×1661205441³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1661205399 and 1661205408.

It is not an unprimeable number, because it can be changed into a prime (1661205451) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110290 + ... + 124443.

It is an arithmetic number, because the mean of its divisors is an integer number (158680184).

Almost surely, 2^1661205441 is an apocalyptic number.

It is an amenable number.

1661205441 is a deficient number, since it is larger than the sum of its proper divisors (877677503).

1661205441 is a wasteful number, since it uses less digits than its factorization.

1661205441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235080.

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 1661205441 is about 40757.8880831674. Note that the first 3 decimals coincide. The cubic root of 1661205441 is about 1184.3346846584.

The spelling of 1661205441 in words is "one billion, six hundred sixty-one million, two hundred five thousand, four hundred forty-one".