210691031121 has 10 divisors (see below), whose sum is σ = 314735984882. Its totient is φ = 140460687360.

The previous prime is 210691031093. The next prime is 210691031123. The reversal of 210691031121 is 121130196012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 191878165521 + 18812865600 = 438039^2 + 137160^2 .

It is not a de Polignac number, because 210691031121 - 2¹⁹ = 210690506833 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (210691031123) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1300561840 + ... + 1300562001.

Almost surely, 2^210691031121 is an apocalyptic number.

It is an amenable number.

210691031121 is a deficient number, since it is larger than the sum of its proper divisors (104044953761).

210691031121 is an equidigital number, since it uses as much as digits as its factorization.

210691031121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2601123853 (or 2601123844 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The spelling of 210691031121 in words is "two hundred ten billion, six hundred ninety-one million, thirty-one thousand, one hundred twenty-one".