1661465775 has 24 divisors (see below), whose sum is σ = 2751855120. Its totient is φ = 884535040.

The previous prime is 1661465759. The next prime is 1661465807. The reversal of 1661465775 is 5775641661.

It is not a de Polignac number, because 1661465775 - 2⁴ = 1661465759 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23209 + ... + 62141.

It is an arithmetic number, because the mean of its divisors is an integer number (114660630).

Almost surely, 2^1661465775 is an apocalyptic number.

1661465775 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1661465775 is a deficient number, since it is larger than the sum of its proper divisors (1090389345).

1661465775 is a wasteful number, since it uses less digits than its factorization.

1661465775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39515 (or 39510 counting only the distinct ones).

The product of its digits is 1058400, while the sum is 48.

The square root of 1661465775 is about 40761.0816220571. The cubic root of 1661465775 is about 1184.3965486666.

The spelling of 1661465775 in words is "one billion, six hundred sixty-one million, four hundred sixty-five thousand, seven hundred seventy-five".