206621020121157 has 12 divisors (see below), whose sum is σ = 300353556498060. Its totient is φ = 136869975111168.

The previous prime is 206621020121119. The next prime is 206621020121221. The reversal of 206621020121157 is 751121020126602.

206621020121157 is a `hidden beast` number, since 2 + 0 + 6 + 621 + 0 + 2 + 0 + 1 + 21 + 1 + 5 + 7 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 59497681148676 + 147123338972481 = 7713474^2 + 12129441^2 .

It is not a de Polignac number, because 206621020121157 - 2⁶ = 206621020121093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206621020121107) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 73114301532 + ... + 73114304357.

It is an arithmetic number, because the mean of its divisors is an integer number (25029463041505).

Almost surely, 2^{206621020121157} is an apocalyptic number.

It is an amenable number.

206621020121157 is a deficient number, since it is larger than the sum of its proper divisors (93732536376903).

206621020121157 is a wasteful number, since it uses less digits than its factorization.

206621020121157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146228606052 (or 146228606049 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

Adding to 206621020121157 its reverse (751121020126602), we get a palindrome (957742040247759).

Subtracting 206621020121157 from its reverse (751121020126602), we obtain a palindrome (544500000005445).

The spelling of 206621020121157 in words is "two hundred six trillion, six hundred twenty-one billion, twenty million, one hundred twenty-one thousand, one hundred fifty-seven".