1661252365 has 16 divisors (see below), whose sum is σ = 2143077120. Its totient is φ = 1232262720.

The previous prime is 1661252357. The next prime is 1661252389. The reversal of 1661252365 is 5632521661.

It is not a de Polignac number, because 1661252365 - 2³ = 1661252357 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 181566 + ... + 190495.

It is an arithmetic number, because the mean of its divisors is an integer number (133942320).

Almost surely, 2^1661252365 is an apocalyptic number.

It is an amenable number.

1661252365 is a deficient number, since it is larger than the sum of its proper divisors (481824755).

1661252365 is a wasteful number, since it uses less digits than its factorization.

1661252365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372132.

The product of its digits is 64800, while the sum is 37.

The square root of 1661252365 is about 40758.4637222749. The cubic root of 1661252365 is about 1184.3458358374.

It can be divided in two parts, 166125 and 2365, that added together give a triangular number (168490 = T₅₈₀).

The spelling of 1661252365 in words is "one billion, six hundred sixty-one million, two hundred fifty-two thousand, three hundred sixty-five".