1720706121 has 6 divisors (see below), whose sum is σ = 2485464410. Its totient is φ = 1147137408.

The previous prime is 1720706093. The next prime is 1720706129. The reversal of 1720706121 is 1216070271.

It can be written as a sum of positive squares in only one way, i.e., 1076561721 + 644144400 = 32811^2 + 25380^2 .

It is not a de Polignac number, because 1720706121 - 2²³ = 1712317513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1720706129) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 95594776 + ... + 95594793.

Almost surely, 2^1720706121 is an apocalyptic number.

It is an amenable number.

1720706121 is a deficient number, since it is larger than the sum of its proper divisors (764758289).

1720706121 is a wasteful number, since it uses less digits than its factorization.

1720706121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191189575 (or 191189572 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 27.

The square root of 1720706121 is about 41481.3948777039. The cubic root of 1720706121 is about 1198.3092209240.

Adding to 1720706121 its reverse (1216070271), we get a palindrome (2936776392).

The spelling of 1720706121 in words is "one billion, seven hundred twenty million, seven hundred six thousand, one hundred twenty-one".