19730681 has 4 divisors (see below), whose sum is σ = 20103012. Its totient is φ = 19358352.

The previous prime is 19730671. The next prime is 19730699. The reversal of 19730681 is 18603791.

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 16810000 + 2920681 = 4100^2 + 1709^2 .

It is a cyclic number.

It is not a de Polignac number, because 19730681 - 2¹⁴ = 19714297 is a prime.

It is a super-2 number, since 2×19730681² = 778599545447522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19730671) 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, 186086 + ... + 186191.

It is an arithmetic number, because the mean of its divisors is an integer number (5025753).

Almost surely, 2^19730681 is an apocalyptic number.

It is an amenable number.

19730681 is a deficient number, since it is larger than the sum of its proper divisors (372331).

19730681 is an equidigital number, since it uses as much as digits as its factorization.

19730681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372330.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 19730681 is about 4441.9231195508. The cubic root of 19730681 is about 270.2178443081.

The spelling of 19730681 in words is "nineteen million, seven hundred thirty thousand, six hundred eighty-one".