78694641 has 9 divisors (see below), whose sum is σ = 113708491. Its totient is φ = 52445352.

The previous prime is 78694639. The next prime is 78694667. The reversal of 78694641 is 14649687.

The square root of 78694641 is 8871.

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., 14630625 + 64064016 = 3825^2 + 8004^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 78694641 - 2¹ = 78694639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78694691) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 25135 + ... + 28091.

Almost surely, 2^78694641 is an apocalyptic number.

78694641 is the 8871-st square number.

78694641 is the 4436-th centered octagonal number.

It is an amenable number.

78694641 is a deficient number, since it is larger than the sum of its proper divisors (35013850).

78694641 is an frugal number, since it uses more digits than its factorization.

78694641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5920 (or 2960 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The cubic root of 78694641 is about 428.5304821357.

The spelling of 78694641 in words is "seventy-eight million, six hundred ninety-four thousand, six hundred forty-one".