21621349763 has 32 divisors (see below), whose sum is σ = 25085491200. Its totient is φ = 18468777600.

The previous prime is 21621349753. The next prime is 21621349769. The reversal of 21621349763 is 36794312612.

It is a Cunningham number, because it is equal to 147042²-1.

It is not a de Polignac number, because 21621349763 - 2⁴ = 21621349747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21621349769) 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 31 ways as a sum of consecutive naturals, for example, 1905878 + ... + 1917188.

It is an arithmetic number, because the mean of its divisors is an integer number (783921600).

Almost surely, 2^21621349763 is an apocalyptic number.

21621349763 is a deficient number, since it is larger than the sum of its proper divisors (3464141437).

21621349763 is a wasteful number, since it uses less digits than its factorization.

21621349763 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11523.

The product of its digits is 326592, while the sum is 44.

The spelling of 21621349763 in words is "twenty-one billion, six hundred twenty-one million, three hundred forty-nine thousand, seven hundred sixty-three".