1661003641 has 16 divisors (see below), whose sum is σ = 1852865280. Its totient is φ = 1476033280.

The previous prime is 1661003629. The next prime is 1661003711. The reversal of 1661003641 is 1463001661.

It is a cyclic number.

It is not a de Polignac number, because 1661003641 - 2⁹ = 1661003129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1661000641) 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, 571905 + ... + 574801.

It is an arithmetic number, because the mean of its divisors is an integer number (115804080).

Almost surely, 2^1661003641 is an apocalyptic number.

1661003641 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1661003641 is a deficient number, since it is larger than the sum of its proper divisors (191861639).

1661003641 is a wasteful number, since it uses less digits than its factorization.

1661003641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4064.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 1661003641 is about 40755.4124135678. The cubic root of 1661003641 is about 1184.2867258264.

The spelling of 1661003641 in words is "one billion, six hundred sixty-one million, three thousand, six hundred forty-one".