20840977 has 2 divisors, whose sum is σ = 20840978. Its totient is φ = 20840976.

The previous prime is 20840951. The next prime is 20840987. The reversal of 20840977 is 77904802.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18284176 + 2556801 = 4276^2 + 1599^2 .

It is a cyclic number.

It is not a de Polignac number, because 20840977 - 2¹¹ = 20838929 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20840987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10420488 + 10420489.

It is an arithmetic number, because the mean of its divisors is an integer number (10420489).

Almost surely, 2^20840977 is an apocalyptic number.

It is an amenable number.

20840977 is a deficient number, since it is larger than the sum of its proper divisors (1).

20840977 is an equidigital number, since it uses as much as digits as its factorization.

20840977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 20840977 is about 4565.1918908190. The cubic root of 20840977 is about 275.1942517348.

The spelling of 20840977 in words is "twenty million, eight hundred forty thousand, nine hundred seventy-seven".