21275776621 has 16 divisors (see below), whose sum is σ = 23784336576. Its totient is φ = 18863280000.

The previous prime is 21275776583. The next prime is 21275776637. The reversal of 21275776621 is 12667757212.

It is not a de Polignac number, because 21275776621 - 2⁷ = 21275776493 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21275776421) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1658251 + ... + 1671031.

It is an arithmetic number, because the mean of its divisors is an integer number (1486521036).

Almost surely, 2^21275776621 is an apocalyptic number.

It is an amenable number.

21275776621 is a deficient number, since it is larger than the sum of its proper divisors (2508559955).

21275776621 is a wasteful number, since it uses less digits than its factorization.

21275776621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16524.

The product of its digits is 493920, while the sum is 46.

The spelling of 21275776621 in words is "twenty-one billion, two hundred seventy-five million, seven hundred seventy-six thousand, six hundred twenty-one".