21729048784776 has 48 divisors (see below), whose sum is σ = 61408181352960. Its totient is φ = 6928102510560.

The previous prime is 21729048784771. The next prime is 21729048784813. The reversal of 21729048784776 is 67748784092712.

21729048784776 is a `hidden beast` number, since 2 + 1 + 72 + 9 + 0 + 4 + 87 + 8 + 477 + 6 = 666.

It is a super-2 number, since 2×21729048784776² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is not an unprimeable number, because it can be changed into a prime (21729048784771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6560701480 + ... + 6560704791.

It is an arithmetic number, because the mean of its divisors is an integer number (1279337111520).

Almost surely, 2^{21729048784776} is an apocalyptic number.

It is an amenable number.

21729048784776 is an abundant number, since it is smaller than the sum of its proper divisors (39679132568184).

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

21729048784776 is a wasteful number, since it uses less digits than its factorization.

21729048784776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13121406306 (or 13121406299 counting only the distinct ones).

The product of its (nonzero) digits is 531062784, while the sum is 72.

The spelling of 21729048784776 in words is "twenty-one trillion, seven hundred twenty-nine billion, forty-eight million, seven hundred eighty-four thousand, seven hundred seventy-six".