1051721765 has 4 divisors (see below), whose sum is σ = 1262066124. Its totient is φ = 841377408.

The previous prime is 1051721761. The next prime is 1051721767. The reversal of 1051721765 is 5671271501.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 235991044 + 815730721 = 15362^2 + 28561^2 .

It is a cyclic number.

It is not a de Polignac number, because 1051721765 - 2² = 1051721761 is a prime.

It is a super-2 number, since 2×1051721765² = 2212237341949430450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1051721761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 105172172 + ... + 105172181.

It is an arithmetic number, because the mean of its divisors is an integer number (315516531).

Almost surely, 2^1051721765 is an apocalyptic number.

It is an amenable number.

1051721765 is a deficient number, since it is larger than the sum of its proper divisors (210344359).

1051721765 is an equidigital number, since it uses as much as digits as its factorization.

1051721765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210344358.

The product of its (nonzero) digits is 14700, while the sum is 35.

The square root of 1051721765 is about 32430.2600205425. The cubic root of 1051721765 is about 1016.9516076117.

The spelling of 1051721765 in words is "one billion, fifty-one million, seven hundred twenty-one thousand, seven hundred sixty-five".