78138751 has 8 divisors (see below), whose sum is σ = 82345824. Its totient is φ = 73999200.

The previous prime is 78138727. The next prime is 78138757. The reversal of 78138751 is 15783187.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 78138751 - 2¹¹ = 78136703 is a prime.

It is a super-2 number, since 2×78138751² = 12211328815680002, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78138757) 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, 14496 + ... + 19141.

It is an arithmetic number, because the mean of its divisors is an integer number (10293228).

Almost surely, 2^78138751 is an apocalyptic number.

78138751 is a deficient number, since it is larger than the sum of its proper divisors (4207073).

78138751 is a wasteful number, since it uses less digits than its factorization.

78138751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33761.

The product of its digits is 47040, while the sum is 40.

The square root of 78138751 is about 8839.6126046338. The cubic root of 78138751 is about 427.5190666690.

The spelling of 78138751 in words is "seventy-eight million, one hundred thirty-eight thousand, seven hundred fifty-one".