211398567961 has 27 divisors (see below), whose sum is σ = 259611685119. Its totient is φ = 171612338688.

The previous prime is 211398567917. The next prime is 211398567983. The reversal of 211398567961 is 169765893112.

The square root of 211398567961 is 459781.

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., 3046488025 + 208352079936 = 55195^2 + 456456^2 .

It is not a de Polignac number, because 211398567961 - 2¹⁷ = 211398436889 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 211398567896 and 211398567905.

It is not an unprimeable number, because it can be changed into a prime (211398562961) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 61149145 + ... + 61152601.

It is an arithmetic number, because the mean of its divisors is an integer number (9615247597).

Almost surely, 2^211398567961 is an apocalyptic number.

211398567961 is the 459781-st square number.

211398567961 is the 229891-st centered octagonal number.

It is an amenable number.

211398567961 is a deficient number, since it is larger than the sum of its proper divisors (48213117158).

211398567961 is an frugal number, since it uses more digits than its factorization.

211398567961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6966 (or 3483 counting only the distinct ones).

The product of its digits is 4898880, while the sum is 58.

The spelling of 211398567961 in words is "two hundred eleven billion, three hundred ninety-eight million, five hundred sixty-seven thousand, nine hundred sixty-one".