21277155168 has 180 divisors, whose sum is σ = 66045214620. Its totient is φ = 6718806144.

The previous prime is 21277155143. The next prime is 21277155223. The reversal of 21277155168 is 86155177212.

21277155168 is a `hidden beast` number, since 2 + 1 + 27 + 71 + 551 + 6 + 8 = 666.

It is a congruent number.

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 in 29 ways as a sum of consecutive naturals, for example, 924343 + ... + 947081.

It is an arithmetic number, because the mean of its divisors is an integer number (366917859).

Almost surely, 2^21277155168 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21277155168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33022607310).

21277155168 is an abundant number, since it is smaller than the sum of its proper divisors (44768059452).

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

21277155168 is a wasteful number, since it uses less digits than its factorization.

21277155168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22799 (or 22763 counting only the distinct ones).

The product of its digits is 235200, while the sum is 45.

The spelling of 21277155168 in words is "twenty-one billion, two hundred seventy-seven million, one hundred fifty-five thousand, one hundred sixty-eight".