20521017206 has 4 divisors (see below), whose sum is σ = 30781525812. Its totient is φ = 10260508602.

The previous prime is 20521017199. The next prime is 20521017227. The reversal of 20521017206 is 60271012502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60271012502 = 2 ⋅30135506251.

It is a super-2 number, since 2×20521017206² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5130254300 + ... + 5130254303.

It is an arithmetic number, because the mean of its divisors is an integer number (7695381453).

Almost surely, 2^20521017206 is an apocalyptic number.

20521017206 is a deficient number, since it is larger than the sum of its proper divisors (10260508606).

20521017206 is a wasteful number, since it uses less digits than its factorization.

20521017206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10260508605.

The product of its (nonzero) digits is 1680, while the sum is 26.

Adding to 20521017206 its reverse (60271012502), we get a palindrome (80792029708).

The spelling of 20521017206 in words is "twenty billion, five hundred twenty-one million, seventeen thousand, two hundred six".