1720315257 has 4 divisors (see below), whose sum is σ = 2293753680. Its totient is φ = 1146876836.

The previous prime is 1720315211. The next prime is 1720315279. The reversal of 1720315257 is 7525130271.

It is a happy number.

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 1720315257 - 2¹² = 1720311161 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1720315057) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 286719207 + ... + 286719212.

It is an arithmetic number, because the mean of its divisors is an integer number (573438420).

Almost surely, 2^1720315257 is an apocalyptic number.

It is an amenable number.

1720315257 is a deficient number, since it is larger than the sum of its proper divisors (573438423).

1720315257 is an equidigital number, since it uses as much as digits as its factorization.

1720315257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 573438422.

The product of its (nonzero) digits is 14700, while the sum is 33.

The square root of 1720315257 is about 41476.6832931468. The cubic root of 1720315257 is about 1198.2184807721.

The spelling of 1720315257 in words is "one billion, seven hundred twenty million, three hundred fifteen thousand, two hundred fifty-seven".