78389690 has 8 divisors (see below), whose sum is σ = 141101460. Its totient is φ = 31355872.

The previous prime is 78389671. The next prime is 78389711. The reversal of 78389690 is 9698387.

It can be written as a sum of positive squares in 2 ways, for example, as 74978281 + 3411409 = 8659^2 + 1847^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×78389690² = 12289886996592200, 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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3919475 + ... + 3919494.

Almost surely, 2^78389690 is an apocalyptic number.

78389690 is a deficient number, since it is larger than the sum of its proper divisors (62711770).

78389690 is a wasteful number, since it uses less digits than its factorization.

78389690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7838976.

The product of its (nonzero) digits is 653184, while the sum is 50.

The square root of 78389690 is about 8853.7952314248. The cubic root of 78389690 is about 427.9762302285.

The spelling of 78389690 in words is "seventy-eight million, three hundred eighty-nine thousand, six hundred ninety".