21000555412 has 6 divisors (see below), whose sum is σ = 36750971978. Its totient is φ = 10500277704.

The previous prime is 21000555397. The next prime is 21000555419. The reversal of 21000555412 is 21455500012.

It can be written as a sum of positive squares in only one way, i.e., 16244522116 + 4756033296 = 127454^2 + 68964^2 .

It is a super-2 number, since 2×21000555412² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000555419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2625069423 + ... + 2625069430.

Almost surely, 2^21000555412 is an apocalyptic number.

It is an amenable number.

21000555412 is a deficient number, since it is larger than the sum of its proper divisors (15750416566).

21000555412 is a wasteful number, since it uses less digits than its factorization.

21000555412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5250138857 (or 5250138855 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 25.

The spelling of 21000555412 in words is "twenty-one billion, five hundred fifty-five thousand, four hundred twelve".