21375651812 has 6 divisors (see below), whose sum is σ = 37407390678. Its totient is φ = 10687825904.

The previous prime is 21375651779. The next prime is 21375651821. The reversal of 21375651812 is 21815657312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 21244228516 + 131423296 = 145754^2 + 11464^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21375651812.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2671956473 + ... + 2671956480.

It is an arithmetic number, because the mean of its divisors is an integer number (6234565113).

Almost surely, 2^21375651812 is an apocalyptic number.

It is an amenable number.

21375651812 is a deficient number, since it is larger than the sum of its proper divisors (16031738866).

21375651812 is a wasteful number, since it uses less digits than its factorization.

21375651812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5343912957 (or 5343912955 counting only the distinct ones).

The product of its digits is 100800, while the sum is 41.

The spelling of 21375651812 in words is "twenty-one billion, three hundred seventy-five million, six hundred fifty-one thousand, eight hundred twelve".