21044200477 has 2 divisors, whose sum is σ = 21044200478. Its totient is φ = 21044200476.

The previous prime is 21044200427. The next prime is 21044200493. The reversal of 21044200477 is 77400244012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11520587556 + 9523612921 = 107334^2 + 97589^2 .

It is a cyclic number.

It is not a de Polignac number, because 21044200477 - 2¹⁵ = 21044167709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21044200427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10522100238 + 10522100239.

It is an arithmetic number, because the mean of its divisors is an integer number (10522100239).

Almost surely, 2^21044200477 is an apocalyptic number.

It is an amenable number.

21044200477 is a deficient number, since it is larger than the sum of its proper divisors (1).

21044200477 is an equidigital number, since it uses as much as digits as its factorization.

21044200477 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12544, while the sum is 31.

Adding to 21044200477 its reverse (77400244012), we get a palindrome (98444444489).

The spelling of 21044200477 in words is "twenty-one billion, forty-four million, two hundred thousand, four hundred seventy-seven".