21746145977 has 2 divisors, whose sum is σ = 21746145978. Its totient is φ = 21746145976.

The previous prime is 21746145937. The next prime is 21746146001. The reversal of 21746145977 is 77954164712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18230130361 + 3516015616 = 135019^2 + 59296^2 .

It is a cyclic number.

It is not a de Polignac number, because 21746145977 - 2⁶ = 21746145913 is a prime.

It is not a weakly prime, because it can be changed into another prime (21746145907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10873072988 + 10873072989.

It is an arithmetic number, because the mean of its divisors is an integer number (10873072989).

Almost surely, 2^21746145977 is an apocalyptic number.

It is an amenable number.

21746145977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21746145977 is an equidigital number, since it uses as much as digits as its factorization.

21746145977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2963520, while the sum is 53.

The spelling of 21746145977 in words is "twenty-one billion, seven hundred forty-six million, one hundred forty-five thousand, nine hundred seventy-seven".