212163665773921 has 9 divisors (see below), whose sum is σ = 212771555096979. Its totient is φ = 211557508383936.

The previous prime is 212163665773883. The next prime is 212163665773931. The reversal of 212163665773921 is 129377566361212.

The square root of 212163665773921 is 14565839.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 86195905430625 + 125967760343296 = 9284175^2 + 11223536^2 .

It is not a de Polignac number, because 212163665773921 - 2²⁵ = 212163632219489 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 212163665773921.

It is not an unprimeable number, because it can be changed into a prime (212163665773931) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 5141720536 + ... + 5141761798.

Almost surely, 2^{212163665773921} is an apocalyptic number.

212163665773921 is the 14565839-th square number.

212163665773921 is the 7282920-th centered octagonal number.

It is an amenable number.

212163665773921 is a deficient number, since it is larger than the sum of its proper divisors (607889323058).

212163665773921 is an frugal number, since it uses more digits than its factorization.

212163665773921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83232 (or 41616 counting only the distinct ones).

The product of its digits is 34292160, while the sum is 61.

The spelling of 212163665773921 in words is "two hundred twelve trillion, one hundred sixty-three billion, six hundred sixty-five million, seven hundred seventy-three thousand, nine hundred twenty-one".