78378990 has 32 divisors (see below), whose sum is σ = 198011520. Its totient is φ = 19800864.

The previous prime is 78378941. The next prime is 78378991. The reversal of 78378990 is 9987387.

It is a happy number.

It is a super-2 number, since 2×78378990² = 12286532146840200, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78378991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68184 + ... + 69323.

It is an arithmetic number, because the mean of its divisors is an integer number (6187860).

Almost surely, 2^78378990 is an apocalyptic number.

78378990 is an abundant number, since it is smaller than the sum of its proper divisors (119632530).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78378990 is a wasteful number, since it uses less digits than its factorization.

78378990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137536.

The product of its (nonzero) digits is 762048, while the sum is 51.

The square root of 78378990 is about 8853.1909501603. The cubic root of 78378990 is about 427.9567567747.

The spelling of 78378990 in words is "seventy-eight million, three hundred seventy-eight thousand, nine hundred ninety".