20776729 has 4 divisors (see below), whose sum is σ = 20797876. Its totient is φ = 20755584.

The previous prime is 20776711. The next prime is 20776739. The reversal of 20776729 is 92767702.

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 11042329 + 9734400 = 3323^2 + 3120^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20776729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20776691 and 20776700.

It is not an unprimeable number, because it can be changed into a prime (20776739) 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, 9024 + ... + 11089.

It is an arithmetic number, because the mean of its divisors is an integer number (5199469).

Almost surely, 2^20776729 is an apocalyptic number.

It is an amenable number.

20776729 is a deficient number, since it is larger than the sum of its proper divisors (21147).

20776729 is a wasteful number, since it uses less digits than its factorization.

20776729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21146.

The product of its (nonzero) digits is 74088, while the sum is 40.

The square root of 20776729 is about 4558.1497342672. The cubic root of 20776729 is about 274.9111735155.

The spelling of 20776729 in words is "twenty million, seven hundred seventy-six thousand, seven hundred twenty-nine".