1720681394 has 12 divisors (see below), whose sum is σ = 2617140906. Its totient is φ = 848308032.

The previous prime is 1720681393. The next prime is 1720681427. The reversal of 1720681394 is 4931860271.

It can be written as a sum of positive squares in 3 ways, for example, as 1279135225 + 441546169 = 35765^2 + 21013^2 .

It is not an unprimeable number, because it can be changed into a prime (1720681393) 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, 499502 + ... + 502934.

Almost surely, 2^1720681394 is an apocalyptic number.

1720681394 is a deficient number, since it is larger than the sum of its proper divisors (896459512).

1720681394 is an frugal number, since it uses more digits than its factorization.

1720681394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6941 (or 3508 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 1720681394 is about 41481.0968273502. The cubic root of 1720681394 is about 1198.3034808901.

The spelling of 1720681394 in words is "one billion, seven hundred twenty million, six hundred eighty-one thousand, three hundred ninety-four".