20772581 has 2 divisors, whose sum is σ = 20772582. Its totient is φ = 20772580.

The previous prime is 20772559. The next prime is 20772593. The reversal of 20772581 is 18527702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14371681 + 6400900 = 3791^2 + 2530^2 .

It is a cyclic number.

It is not a de Polignac number, because 20772581 - 2⁶ = 20772517 is a prime.

It is a super-2 number, since 2×20772581² = 863000242803122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20772481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10386290 + 10386291.

It is an arithmetic number, because the mean of its divisors is an integer number (10386291).

Almost surely, 2^20772581 is an apocalyptic number.

It is an amenable number.

20772581 is a deficient number, since it is larger than the sum of its proper divisors (1).

20772581 is an equidigital number, since it uses as much as digits as its factorization.

20772581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7840, while the sum is 32.

The square root of 20772581 is about 4557.6947023687. The cubic root of 20772581 is about 274.8928772854.

The spelling of 20772581 in words is "twenty million, seven hundred seventy-two thousand, five hundred eighty-one".