78394990 has 16 divisors (see below), whose sum is σ = 149411952. Its totient is φ = 29513344.

The previous prime is 78394963. The next prime is 78394991. The reversal of 78394990 is 9949387.

It is a super-2 number, since 2×78394990² = 12291548914200200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78394991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 230404 + ... + 230743.

It is an arithmetic number, because the mean of its divisors is an integer number (9338247).

Almost surely, 2^78394990 is an apocalyptic number.

78394990 is a deficient number, since it is larger than the sum of its proper divisors (71016962).

78394990 is a wasteful number, since it uses less digits than its factorization.

78394990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461171.

The product of its (nonzero) digits is 489888, while the sum is 49.

The square root of 78394990 is about 8854.0945330395. The cubic root of 78394990 is about 427.9858753018.

The spelling of 78394990 in words is "seventy-eight million, three hundred ninety-four thousand, nine hundred ninety".