78621794 has 4 divisors (see below), whose sum is σ = 117932694. Its totient is φ = 39310896.

The previous prime is 78621793. The next prime is 78621811. The reversal of 78621794 is 49712687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 49712687 = 43 ⋅1156109.

It can be written as a sum of positive squares in only one way, i.e., 67486225 + 11135569 = 8215^2 + 3337^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (78621793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19655447 + ... + 19655450.

Almost surely, 2^78621794 is an apocalyptic number.

78621794 is a deficient number, since it is larger than the sum of its proper divisors (39310900).

78621794 is a wasteful number, since it uses less digits than its factorization.

78621794 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39310899.

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

The square root of 78621794 is about 8866.8931424710. The cubic root of 78621794 is about 428.3982122331.

The spelling of 78621794 in words is "seventy-eight million, six hundred twenty-one thousand, seven hundred ninety-four".