1075720021 has 2 divisors, whose sum is σ = 1075720022. Its totient is φ = 1075720020.

The previous prime is 1075720013. The next prime is 1075720031. The reversal of 1075720021 is 1200275701.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 990360900 + 85359121 = 31470^2 + 9239^2 .

It is a cyclic number.

It is not a de Polignac number, because 1075720021 - 2³ = 1075720013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1075720001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 537860010 + 537860011.

It is an arithmetic number, because the mean of its divisors is an integer number (537860011).

Almost surely, 2^1075720021 is an apocalyptic number.

It is an amenable number.

1075720021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1075720021 is an equidigital number, since it uses as much as digits as its factorization.

1075720021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 980, while the sum is 25.

The square root of 1075720021 is about 32798.1710008348. The cubic root of 1075720021 is about 1024.6284660991.

Adding to 1075720021 its reverse (1200275701), we get a palindrome (2275995722).

The spelling of 1075720021 in words is "one billion, seventy-five million, seven hundred twenty thousand, twenty-one".