21016661012 has 6 divisors (see below), whose sum is σ = 36779156778. Its totient is φ = 10508330504.

The previous prime is 21016660999. The next prime is 21016661041.

21016661012 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 20861758096 + 154902916 = 144436^2 + 12446^2 .

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, 2627082623 + ... + 2627082630.

It is an arithmetic number, because the mean of its divisors is an integer number (6129859463).

Almost surely, 2^21016661012 is an apocalyptic number.

It is an amenable number.

21016661012 is a deficient number, since it is larger than the sum of its proper divisors (15762495766).

21016661012 is a wasteful number, since it uses less digits than its factorization.

21016661012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5254165257 (or 5254165255 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The spelling of 21016661012 in words is "twenty-one billion, sixteen million, six hundred sixty-one thousand, twelve".