21275841784 has 16 divisors (see below), whose sum is σ = 39894075000. Its totient is φ = 10637421792.

The previous prime is 21275841779. The next prime is 21275841791. The reversal of 21275841784 is 48714857212.

It is a happy number.

It is a super-2 number, since 2×21275841784² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 169467 + ... + 266965.

Almost surely, 2^21275841784 is an apocalyptic number.

It is an amenable number.

21275841784 is a deficient number, since it is larger than the sum of its proper divisors (18618233216).

21275841784 is a wasteful number, since it uses less digits than its factorization.

21275841784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124782 (or 124778 counting only the distinct ones).

The product of its digits is 1003520, while the sum is 49.

The spelling of 21275841784 in words is "twenty-one billion, two hundred seventy-five million, eight hundred forty-one thousand, seven hundred eighty-four".