21021031067977 has 2 divisors, whose sum is σ = 21021031067978. Its totient is φ = 21021031067976.

The previous prime is 21021031067909. The next prime is 21021031068041. The reversal of 21021031067977 is 77976013012012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17649165590281 + 3371865477696 = 4201091^2 + 1836264^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021031067977 - 2⁴³ = 12224938045769 is a prime.

It is not a weakly prime, because it can be changed into another prime (21021031064977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510515533988 + 10510515533989.

It is an arithmetic number, because the mean of its divisors is an integer number (10510515533989).

Almost surely, 2^{21021031067977} is an apocalyptic number.

It is an amenable number.

21021031067977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021031067977 is an equidigital number, since it uses as much as digits as its factorization.

21021031067977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 222264, while the sum is 46.

Adding to 21021031067977 its reverse (77976013012012), we get a palindrome (98997044079989).

The spelling of 21021031067977 in words is "twenty-one trillion, twenty-one billion, thirty-one million, sixty-seven thousand, nine hundred seventy-seven".