1951985665 has 16 divisors (see below), whose sum is σ = 2720897280. Its totient is φ = 1316560320.

The previous prime is 1951985557. The next prime is 1951985681. The reversal of 1951985665 is 5665891591.

It is not a de Polignac number, because 1951985665 - 2⁷ = 1951985537 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 455005 + ... + 459274.

It is an arithmetic number, because the mean of its divisors is an integer number (170056080).

Almost surely, 2^1951985665 is an apocalyptic number.

It is an amenable number.

1951985665 is a deficient number, since it is larger than the sum of its proper divisors (768911615).

1951985665 is an equidigital number, since it uses as much as digits as its factorization.

1951985665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 914352.

The product of its digits is 2916000, while the sum is 55.

The square root of 1951985665 is about 44181.2818397113. The cubic root of 1951985665 is about 1249.7568945895.

The spelling of 1951985665 in words is "one billion, nine hundred fifty-one million, nine hundred eighty-five thousand, six hundred sixty-five".