78399440001 has 45 divisors (see below), whose sum is σ = 119570323411. Its totient is φ = 51192777168.

The previous prime is 78399439991. The next prime is 78399440003. The reversal of 78399440001 is 10004499387.

The square root of 78399440001 is 279999.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 56517930225 + 21881509776 = 237735^2 + 147924^2 .

It is not a de Polignac number, because 78399440001 - 2¹¹ = 78399437953 is a prime.

It is a super-2 number, since 2×78399440001² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78399440003) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 133559230 + ... + 133559816.

Almost surely, 2^78399440001 is an apocalyptic number.

78399440001 is the 279999-th square number.

78399440001 is the 140000-th centered octagonal number.

It is an amenable number.

78399440001 is a deficient number, since it is larger than the sum of its proper divisors (41170883410).

78399440001 is an frugal number, since it uses more digits than its factorization.

78399440001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1292 (or 643 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

It can be divided in two parts, 78399 and 440001, that added together give a square (518400 = 720²).

The spelling of 78399440001 in words is "seventy-eight billion, three hundred ninety-nine million, four hundred forty thousand, one".