21000021203377 has 2 divisors, whose sum is σ = 21000021203378. Its totient is φ = 21000021203376.

The previous prime is 21000021203323. The next prime is 21000021203407. The reversal of 21000021203377 is 77330212000012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20931347856241 + 68673347136 = 4575079^2 + 262056^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000021203377 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000021203177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500010601688 + 10500010601689.

It is an arithmetic number, because the mean of its divisors is an integer number (10500010601689).

Almost surely, 2^{21000021203377} is an apocalyptic number.

It is an amenable number.

21000021203377 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000021203377 is an equidigital number, since it uses as much as digits as its factorization.

21000021203377 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3528, while the sum is 28.

Adding to 21000021203377 its reverse (77330212000012), we get a palindrome (98330233203389).

The spelling of 21000021203377 in words is "twenty-one trillion, twenty-one million, two hundred three thousand, three hundred seventy-seven".