78198650 has 12 divisors (see below), whose sum is σ = 145449582. Its totient is φ = 31279440.

The previous prime is 78198611. The next prime is 78198667. The reversal of 78198650 is 5689187.

It is a happy number.

It is a Cunningham number, because it is equal to 8843²+1.

It can be written as a sum of positive squares in 3 ways, for example, as 72063121 + 6135529 = 8489^2 + 2477^2 .

It is a super-2 number, since 2×78198650² = 12230057723645000, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 781937 + ... + 782036.

Almost surely, 2^78198650 is an apocalyptic number.

78198650 is a deficient number, since it is larger than the sum of its proper divisors (67250932).

78198650 is a wasteful number, since it uses less digits than its factorization.

78198650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1563985 (or 1563980 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 44.

The square root of 78198650 is about 8843.0000565419. Note that the first 4 decimals coincide. The cubic root of 78198650 is about 427.6282801880.

The spelling of 78198650 in words is "seventy-eight million, one hundred ninety-eight thousand, six hundred fifty".