20681477 has 2 divisors, whose sum is σ = 20681478. Its totient is φ = 20681476.

The previous prime is 20681471. The next prime is 20681491. The reversal of 20681477 is 77418602.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17048641 + 3632836 = 4129^2 + 1906^2 .

It is a cyclic number.

It is not a de Polignac number, because 20681477 - 2¹⁰ = 20680453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20681471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10340738 + 10340739.

It is an arithmetic number, because the mean of its divisors is an integer number (10340739).

Almost surely, 2^20681477 is an apocalyptic number.

It is an amenable number.

20681477 is a deficient number, since it is larger than the sum of its proper divisors (1).

20681477 is an equidigital number, since it uses as much as digits as its factorization.

20681477 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18816, while the sum is 35.

The square root of 20681477 is about 4547.6891934256. The cubic root of 20681477 is about 274.4904149813.

The spelling of 20681477 in words is "twenty million, six hundred eighty-one thousand, four hundred seventy-seven".