20517221079 has 32 divisors (see below), whose sum is σ = 32434022400. Its totient is φ = 12780711360.

The previous prime is 20517221077. The next prime is 20517221083. The reversal of 20517221079 is 97012271502.

20517221079 is a `hidden beast` number, since 205 + 172 + 210 + 79 = 666.

It is not a de Polignac number, because 20517221079 - 2¹ = 20517221077 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20517221077) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 236487 + ... + 311384.

It is an arithmetic number, because the mean of its divisors is an integer number (1013563200).

Almost surely, 2^20517221079 is an apocalyptic number.

20517221079 is a deficient number, since it is larger than the sum of its proper divisors (11916801321).

20517221079 is a wasteful number, since it uses less digits than its factorization.

20517221079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547972 (or 547966 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 36.

The spelling of 20517221079 in words is "twenty billion, five hundred seventeen million, two hundred twenty-one thousand, seventy-nine".