20556217012 has 24 divisors (see below), whose sum is σ = 38345113800. Its totient is φ = 9608586240.

The previous prime is 20556216973. The next prime is 20556217013. The reversal of 20556217012 is 21071265502.

It can be written as a sum of positive squares in 4 ways, for example, as 696643236 + 19859573776 = 26394^2 + 140924^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20556217013) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1004289 + ... + 1024552.

It is an arithmetic number, because the mean of its divisors is an integer number (1597713075).

Almost surely, 2^20556217012 is an apocalyptic number.

It is an amenable number.

20556217012 is a deficient number, since it is larger than the sum of its proper divisors (17788896788).

20556217012 is a wasteful number, since it uses less digits than its factorization.

20556217012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2029011 (or 2029009 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 31.

The spelling of 20556217012 in words is "twenty billion, five hundred fifty-six million, two hundred seventeen thousand, twelve".