781243477728 has 96 divisors (see below), whose sum is σ = 2387951870976. Its totient is φ = 219000857088.

The previous prime is 781243477723. The next prime is 781243477739. The reversal of 781243477728 is 827774342187.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×781243477728² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (60) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (781243477723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10931976 + ... + 11003207.

It is an arithmetic number, because the mean of its divisors is an integer number (24874498656).

Almost surely, 2^781243477728 is an apocalyptic number.

It is an amenable number.

781243477728 is an abundant number, since it is smaller than the sum of its proper divisors (1606708393248).

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

781243477728 is a wasteful number, since it uses less digits than its factorization.

781243477728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21935256 (or 21935248 counting only the distinct ones).

The product of its digits is 29503488, while the sum is 60.

The spelling of 781243477728 in words is "seven hundred eighty-one billion, two hundred forty-three million, four hundred seventy-seven thousand, seven hundred twenty-eight".