20764681 has 6 divisors (see below), whose sum is σ = 24154890. Its totient is φ = 17798256.

The previous prime is 20764673. The next prime is 20764703. The reversal of 20764681 is 18646702.

It can be written as a sum of positive squares in only one way, i.e., 20385225 + 379456 = 4515^2 + 616^2 .

It is not a de Polignac number, because 20764681 - 2³ = 20764673 is a prime.

It is a super-2 number, since 2×20764681² = 862343954063522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20764651) 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 5 ways as a sum of consecutive naturals, for example, 211836 + ... + 211933.

It is an arithmetic number, because the mean of its divisors is an integer number (4025815).

Almost surely, 2^20764681 is an apocalyptic number.

It is an amenable number.

20764681 is a deficient number, since it is larger than the sum of its proper divisors (3390209).

20764681 is an equidigital number, since it uses as much as digits as its factorization.

20764681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423783 (or 423776 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 20764681 is about 4556.8279537415. The cubic root of 20764681 is about 274.8580247862.

The spelling of 20764681 in words is "twenty million, seven hundred sixty-four thousand, six hundred eighty-one".