21771634464 has 192 divisors, whose sum is σ = 66595737600. Its totient is φ = 6910396416.

The previous prime is 21771634457. The next prime is 21771634471. The reversal of 21771634464 is 46443617712.

21771634464 is a `hidden beast` number, since 2 + 1 + 7 + 7 + 1 + 634 + 4 + 6 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (21771634457) and next prime (21771634471).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1823137 + ... + 1835039.

It is an arithmetic number, because the mean of its divisors is an integer number (346852800).

Almost surely, 2^21771634464 is an apocalyptic number.

21771634464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21771634464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33297868800).

21771634464 is an abundant number, since it is smaller than the sum of its proper divisors (44824103136).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21771634464 is a wasteful number, since it uses less digits than its factorization.

21771634464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12024 (or 12010 counting only the distinct ones).

The product of its digits is 677376, while the sum is 45.

The spelling of 21771634464 in words is "twenty-one billion, seven hundred seventy-one million, six hundred thirty-four thousand, four hundred sixty-four".