20681761 has 8 divisors (see below), whose sum is σ = 21904704. Its totient is φ = 19485840.

The previous prime is 20681723. The next prime is 20681777. The reversal of 20681761 is 16718602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20681761 - 2⁹ = 20681249 is a prime.

It is a super-2 number, since 2×20681761² = 855470476122242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20681701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5170 + ... + 8251.

It is an arithmetic number, because the mean of its divisors is an integer number (2738088).

Almost surely, 2^20681761 is an apocalyptic number.

It is an amenable number.

20681761 is a deficient number, since it is larger than the sum of its proper divisors (1222943).

20681761 is a wasteful number, since it uses less digits than its factorization.

20681761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13511.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 20681761 is about 4547.7204179677. The cubic root of 20681761 is about 274.4916714184.

The spelling of 20681761 in words is "twenty million, six hundred eighty-one thousand, seven hundred sixty-one".