1720661260157 has 4 divisors (see below), whose sum is σ = 1966470011616.
Its totient is φ = 1474852508700.
The previous prime is 1720661260141. The next prime is 1720661260159. The reversal of 1720661260157 is 7510621660271.
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 1720661260157 - 24 = 1720661260141 is a prime.
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (1720661260159) 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, 122904375719 + ... + 122904375732.
It is an arithmetic number, because the mean of its divisors is an integer number (491617502904).
Almost surely, 21720661260157 is an apocalyptic number.
It is an amenable number.
1720661260157 is a deficient number, since it is larger than the sum of its proper divisors (245808751459).
1720661260157 is an equidigital number, since it uses as much as digits as its factorization.
1720661260157 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 245808751458.
The product of its (nonzero) digits is 211680, while the sum is 44.
The spelling of 1720661260157 in words is "one trillion, seven hundred twenty billion, six hundred sixty-one million, two hundred sixty thousand, one hundred fifty-seven".