21287078212 has 6 divisors (see below), whose sum is σ = 37252386878. Its totient is φ = 10643539104.

The previous prime is 21287078209. The next prime is 21287078237.

21287078212 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 20777492736 + 509585476 = 144144^2 + 22574^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2660884773 + ... + 2660884780.

Almost surely, 2^21287078212 is an apocalyptic number.

It is an amenable number.

21287078212 is a deficient number, since it is larger than the sum of its proper divisors (15965308666).

21287078212 is a wasteful number, since it uses less digits than its factorization.

21287078212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5321769557 (or 5321769555 counting only the distinct ones).

The product of its (nonzero) digits is 50176, while the sum is 40.

The spelling of 21287078212 in words is "twenty-one billion, two hundred eighty-seven million, seventy-eight thousand, two hundred twelve".