1720712981 has 4 divisors (see below), whose sum is σ = 1853075532. Its totient is φ = 1588350432.

The previous prime is 1720712971. The next prime is 1720713023. The reversal of 1720712981 is 1892170271.

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 1048140625 + 672572356 = 32375^2 + 25934^2 .

It is a cyclic number.

It is not a de Polignac number, because 1720712981 - 2¹⁰ = 1720711957 is a prime.

It is a super-2 number, since 2×1720712981² = 5921706325963812722, 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 (1720712971) 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, 66181256 + ... + 66181281.

It is an arithmetic number, because the mean of its divisors is an integer number (463268883).

Almost surely, 2^1720712981 is an apocalyptic number.

It is an amenable number.

1720712981 is a deficient number, since it is larger than the sum of its proper divisors (132362551).

1720712981 is a wasteful number, since it uses less digits than its factorization.

1720712981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132362550.

The product of its (nonzero) digits is 14112, while the sum is 38.

The square root of 1720712981 is about 41481.4775652941. The cubic root of 1720712981 is about 1198.3108133691.

The spelling of 1720712981 in words is "one billion, seven hundred twenty million, seven hundred twelve thousand, nine hundred eighty-one".