78387290 has 32 divisors (see below), whose sum is σ = 147102480. Its totient is φ = 30037504.

The previous prime is 78387277. The next prime is 78387301. The reversal of 78387290 is 9278387.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 26388769 + 51998521 = 5137^2 + 7211^2 .

It is a super-2 number, since 2×78387290² = 12289134467088200, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38744 + ... + 40716.

Almost surely, 2^78387290 is an apocalyptic number.

78387290 is a deficient number, since it is larger than the sum of its proper divisors (68715190).

78387290 is a wasteful number, since it uses less digits than its factorization.

78387290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2146.

The product of its (nonzero) digits is 169344, while the sum is 44.

The square root of 78387290 is about 8853.6596952899. The cubic root of 78387290 is about 427.9718625052.

The spelling of 78387290 in words is "seventy-eight million, three hundred eighty-seven thousand, two hundred ninety".