1051551665 has 4 divisors (see below), whose sum is σ = 1261862004. Its totient is φ = 841241328.

The previous prime is 1051551661. The next prime is 1051551673. The reversal of 1051551665 is 5661551501.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5661551501 = 3851 ⋅1470151.

It can be written as a sum of positive squares in 2 ways, for example, as 721620769 + 329930896 = 26863^2 + 18164^2 .

It is a cyclic number.

It is not a de Polignac number, because 1051551665 - 2² = 1051551661 is a prime.

It is a super-2 number, since 2×1051551665² = 2211521808328544450, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1051551661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105155162 + ... + 105155171.

It is an arithmetic number, because the mean of its divisors is an integer number (315465501).

Almost surely, 2^1051551665 is an apocalyptic number.

It is an amenable number.

1051551665 is a deficient number, since it is larger than the sum of its proper divisors (210310339).

1051551665 is an equidigital number, since it uses as much as digits as its factorization.

1051551665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210310338.

The product of its (nonzero) digits is 22500, while the sum is 35.

The square root of 1051551665 is about 32427.6373638290. The cubic root of 1051551665 is about 1016.8967791704.

The spelling of 1051551665 in words is "one billion, fifty-one million, five hundred fifty-one thousand, six hundred sixty-five".