1665550761 has 16 divisors (see below), whose sum is σ = 2538609024. Its totient is φ = 951508224.

The previous prime is 1665550739. The next prime is 1665550781. The reversal of 1665550761 is 1670555661.

It is not a de Polignac number, because 1665550761 - 2⁵ = 1665550729 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1665550721) 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, 113121 + ... + 126993.

It is an arithmetic number, because the mean of its divisors is an integer number (158663064).

Almost surely, 2^1665550761 is an apocalyptic number.

It is an amenable number.

1665550761 is a deficient number, since it is larger than the sum of its proper divisors (873058263).

1665550761 is a wasteful number, since it uses less digits than its factorization.

1665550761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19600.

The product of its (nonzero) digits is 189000, while the sum is 42.

The square root of 1665550761 is about 40811.1597605361. The cubic root of 1665550761 is about 1185.3664319257.

The spelling of 1665550761 in words is "one billion, six hundred sixty-five million, five hundred fifty thousand, seven hundred sixty-one".