21022001977 has 2 divisors, whose sum is σ = 21022001978. Its totient is φ = 21022001976.

The previous prime is 21022001953. The next prime is 21022002011. The reversal of 21022001977 is 77910022012.

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., 12138750976 + 8883251001 = 110176^2 + 94251^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21022001977 is a prime.

It is not a weakly prime, because it can be changed into another prime (21022071977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511000988 + 10511000989.

It is an arithmetic number, because the mean of its divisors is an integer number (10511000989).

Almost surely, 2^21022001977 is an apocalyptic number.

It is an amenable number.

21022001977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022001977 is an equidigital number, since it uses as much as digits as its factorization.

21022001977 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3528, while the sum is 31.

Adding to 21022001977 its reverse (77910022012), we get a palindrome (98932023989).

The spelling of 21022001977 in words is "twenty-one billion, twenty-two million, one thousand, nine hundred seventy-seven".