21002210019977 has 2 divisors, whose sum is σ = 21002210019978. Its totient is φ = 21002210019976.

The previous prime is 21002210019953. The next prime is 21002210020021. The reversal of 21002210019977 is 77991001220012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10753126406416 + 10249083613561 = 3279196^2 + 3201419^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002210019977 - 2¹² = 21002210015881 is a prime.

It is not a weakly prime, because it can be changed into another prime (21002210019577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501105009988 + 10501105009989.

It is an arithmetic number, because the mean of its divisors is an integer number (10501105009989).

Almost surely, 2^{21002210019977} is an apocalyptic number.

It is an amenable number.

21002210019977 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002210019977 is an equidigital number, since it uses as much as digits as its factorization.

21002210019977 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31752, while the sum is 41.

Adding to 21002210019977 its reverse (77991001220012), we get a palindrome (98993211239989).

The spelling of 21002210019977 in words is "twenty-one trillion, two billion, two hundred ten million, nineteen thousand, nine hundred seventy-seven".