78405503781 has 32 divisors (see below), whose sum is σ = 120633080832. Its totient is φ = 44829797760.

The previous prime is 78405503767. The next prime is 78405503783. The reversal of 78405503781 is 18730550487.

It is a happy number.

It is not a de Polignac number, because 78405503781 - 2⁹ = 78405503269 is a prime.

It is a super-2 number, since 2×78405503781² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78405503781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78405503783) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 652135 + ... + 762948.

It is an arithmetic number, because the mean of its divisors is an integer number (3769783776).

Almost surely, 2^78405503781 is an apocalyptic number.

It is an amenable number.

78405503781 is a deficient number, since it is larger than the sum of its proper divisors (42227577051).

78405503781 is a wasteful number, since it uses less digits than its factorization.

78405503781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1415193.

The product of its (nonzero) digits is 940800, while the sum is 48.

The spelling of 78405503781 in words is "seventy-eight billion, four hundred five million, five hundred three thousand, seven hundred eighty-one".