206969493721 has 9 divisors (see below), whose sum is σ = 207837034783. Its totient is φ = 206105564560.

The previous prime is 206969493713. The next prime is 206969493761. The reversal of 206969493721 is 127394969602.

The square root of 206969493721 is 454939.

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., 139867772121 + 67101721600 = 373989^2 + 259040^2 .

It is not a de Polignac number, because 206969493721 - 2³ = 206969493713 is a prime.

It is a super-2 number, since 2×206969493721² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206969493761) 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, 127837050 + ... + 127838668.

Almost surely, 2^206969493721 is an apocalyptic number.

206969493721 is the 454939-th square number.

206969493721 is the 227470-th centered octagonal number.

It is an amenable number.

206969493721 is a deficient number, since it is larger than the sum of its proper divisors (867541062).

206969493721 is an frugal number, since it uses more digits than its factorization.

206969493721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3800 (or 1900 counting only the distinct ones).

The product of its (nonzero) digits is 8817984, while the sum is 58.

The spelling of 206969493721 in words is "two hundred six billion, nine hundred sixty-nine million, four hundred ninety-three thousand, seven hundred twenty-one".