20730681 has 16 divisors (see below), whose sum is σ = 31060800. Its totient is φ = 13663584.

The previous prime is 20730623. The next prime is 20730719. The reversal of 20730681 is 18603702.

It is not a de Polignac number, because 20730681 - 2¹¹ = 20728633 is a prime.

It is a super-2 number, since 2×20730681² = 859522269447522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (20730481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1911 + ... + 6716.

It is an arithmetic number, because the mean of its divisors is an integer number (1941300).

Almost surely, 2^20730681 is an apocalyptic number.

It is an amenable number.

20730681 is a deficient number, since it is larger than the sum of its proper divisors (10330119).

20730681 is an equidigital number, since it uses as much as digits as its factorization.

20730681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8725 (or 8719 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 20730681 is about 4553.0957600297. The cubic root of 20730681 is about 274.7079257138.

The spelling of 20730681 in words is "twenty million, seven hundred thirty thousand, six hundred eighty-one".