21213020177 has 2 divisors, whose sum is σ = 21213020178. Its totient is φ = 21213020176.

The previous prime is 21213020161. The next prime is 21213020207. The reversal of 21213020177 is 77102031212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21161811841 + 51208336 = 145471^2 + 7156^2 .

It is a cyclic number.

It is not a de Polignac number, because 21213020177 - 2⁴ = 21213020161 is a prime.

It is a super-2 number, since 2×21213020177² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21213020077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10606510088 + 10606510089.

It is an arithmetic number, because the mean of its divisors is an integer number (10606510089).

Almost surely, 2^21213020177 is an apocalyptic number.

It is an amenable number.

21213020177 is a deficient number, since it is larger than the sum of its proper divisors (1).

21213020177 is an equidigital number, since it uses as much as digits as its factorization.

21213020177 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1176, while the sum is 26.

Adding to 21213020177 its reverse (77102031212), we get a palindrome (98315051389).

The spelling of 21213020177 in words is "twenty-one billion, two hundred thirteen million, twenty thousand, one hundred seventy-seven".