1720207845 has 24 divisors (see below), whose sum is σ = 3138626400. Its totient is φ = 869157216.

The previous prime is 1720207823. The next prime is 1720207847. The reversal of 1720207845 is 5487020271.

It is not a de Polignac number, because 1720207845 - 2¹⁵ = 1720175077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1720207847) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1005115 + ... + 1006824.

It is an arithmetic number, because the mean of its divisors is an integer number (130776100).

Almost surely, 2^1720207845 is an apocalyptic number.

1720207845 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1720207845 is a deficient number, since it is larger than the sum of its proper divisors (1418418555).

1720207845 is a wasteful number, since it uses less digits than its factorization.

1720207845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2011969 (or 2011966 counting only the distinct ones).

The product of its (nonzero) digits is 31360, while the sum is 36.

The square root of 1720207845 is about 41475.3884249443. The cubic root of 1720207845 is about 1198.1935423736.

The spelling of 1720207845 in words is "one billion, seven hundred twenty million, two hundred seven thousand, eight hundred forty-five".