77721755533400 has 96 divisors (see below), whose sum is σ = 197201129413680. Its totient is φ = 28252349760000.

The previous prime is 77721755533363. The next prime is 77721755533403. The reversal of 77721755533400 is 433555712777.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77721755533403) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 161951 + ... + 12468750.

Almost surely, 2^{77721755533400} 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 77721755533400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98600564706840).

77721755533400 is an abundant number, since it is smaller than the sum of its proper divisors (119479373880280).

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

77721755533400 is a wasteful number, since it uses less digits than its factorization.

77721755533400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12633525 (or 12633516 counting only the distinct ones).

The product of its (nonzero) digits is 21609000, while the sum is 56.

The spelling of 77721755533400 in words is "seventy-seven trillion, seven hundred twenty-one billion, seven hundred fifty-five million, five hundred thirty-three thousand, four hundred".