78198649 has 9 divisors (see below), whose sum is σ = 80706927. Its totient is φ = 75766824.

The previous prime is 78198611. The next prime is 78198667. The reversal of 78198649 is 94689187.

It is a happy number.

The square root of 78198649 is 8843.

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., 69973225 + 8225424 = 8365^2 + 2868^2 .

It is not a de Polignac number, because 78198649 - 2¹³ = 78190457 is a prime.

It is a super-2 number, since 2×78198649² = 12230057410850402, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78198596 and 78198605.

It is not an unprimeable number, because it can be changed into a prime (78198149) 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, 327072 + ... + 327310.

Almost surely, 2^78198649 is an apocalyptic number.

78198649 is the 8843-rd square number.

78198649 is the 4422-nd centered octagonal number.

It is an amenable number.

78198649 is a deficient number, since it is larger than the sum of its proper divisors (2508278).

78198649 is an frugal number, since it uses more digits than its factorization.

78198649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 552 (or 276 counting only the distinct ones).

The product of its digits is 870912, while the sum is 52.

The cubic root of 78198649 is about 427.6282783652.

The spelling of 78198649 in words is "seventy-eight million, one hundred ninety-eight thousand, six hundred forty-nine".