78394490 has 16 divisors (see below), whose sum is σ = 144924552. Its totient is φ = 30510144.

The previous prime is 78394487. The next prime is 78394499. The reversal of 78394490 is 9449387.

It can be written as a sum of positive squares in 4 ways, for example, as 68840209 + 9554281 = 8297^2 + 3091^2 .

It is a super-2 number, since 2×78394490² = 12291392124720200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78394499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105569 + ... + 106308.

Almost surely, 2^78394490 is an apocalyptic number.

78394490 is a deficient number, since it is larger than the sum of its proper divisors (66530062).

78394490 is a wasteful number, since it uses less digits than its factorization.

78394490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211921.

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 78394490 is about 8854.0662974703. The cubic root of 78394490 is about 427.9849654078.

The spelling of 78394490 in words is "seventy-eight million, three hundred ninety-four thousand, four hundred ninety".