78211690 has 8 divisors (see below), whose sum is σ = 140781060. Its totient is φ = 31284672.

The previous prime is 78211681. The next prime is 78211691. The reversal of 78211690 is 9611287.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 64529089 + 13682601 = 8033^2 + 3699^2 .

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

It is a super-2 number, since 2×78211690² = 12234136905312200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78211691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3910575 + ... + 3910594.

Almost surely, 2^78211690 is an apocalyptic number.

78211690 is a deficient number, since it is larger than the sum of its proper divisors (62569370).

78211690 is a wasteful number, since it uses less digits than its factorization.

78211690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7821176.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 78211690 is about 8843.7373321464. The cubic root of 78211690 is about 427.6520485559.

The spelling of 78211690 in words is "seventy-eight million, two hundred eleven thousand, six hundred ninety".