21780777312 has 384 divisors, whose sum is σ = 74159124480. Its totient is φ = 6091407360.

The previous prime is 21780777287. The next prime is 21780777313. The reversal of 21780777312 is 21377708712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21780777313) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 80371737 + ... + 80372007.

It is an arithmetic number, because the mean of its divisors is an integer number (193122720).

Almost surely, 2^21780777312 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 21780777312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37079562240).

21780777312 is an abundant number, since it is smaller than the sum of its proper divisors (52378347168).

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

21780777312 is a wasteful number, since it uses less digits than its factorization.

21780777312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 531 (or 517 counting only the distinct ones).

The product of its (nonzero) digits is 230496, while the sum is 45.

The spelling of 21780777312 in words is "twenty-one billion, seven hundred eighty million, seven hundred seventy-seven thousand, three hundred twelve".