1355090721 has 4 divisors (see below), whose sum is σ = 1806787632. Its totient is φ = 903393812.

The previous prime is 1355090717. The next prime is 1355090731. The reversal of 1355090721 is 1270905531.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1355090721 - 2² = 1355090717 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1355090731) 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, 225848451 + ... + 225848456.

It is an arithmetic number, because the mean of its divisors is an integer number (451696908).

Almost surely, 2^1355090721 is an apocalyptic number.

It is an amenable number.

1355090721 is a deficient number, since it is larger than the sum of its proper divisors (451696911).

1355090721 is an equidigital number, since it uses as much as digits as its factorization.

1355090721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451696910.

The product of its (nonzero) digits is 9450, while the sum is 33.

The square root of 1355090721 is about 36811.5568945406. The cubic root of 1355090721 is about 1106.5969201197.

The spelling of 1355090721 in words is "one billion, three hundred fifty-five million, ninety thousand, seven hundred twenty-one".