78129791 has 8 divisors (see below), whose sum is σ = 79900560. Its totient is φ = 76370112.

The previous prime is 78129761. The next prime is 78129797. The reversal of 78129791 is 19792187.

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 78129791 - 2¹⁴ = 78113407 is a prime.

It is a super-2 number, since 2×78129791² = 12208528483407362, 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 (78129797) 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, 12395 + ... + 17603.

It is an arithmetic number, because the mean of its divisors is an integer number (9987570).

Almost surely, 2^78129791 is an apocalyptic number.

78129791 is a deficient number, since it is larger than the sum of its proper divisors (1770769).

78129791 is a wasteful number, since it uses less digits than its factorization.

78129791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5545.

The product of its digits is 63504, while the sum is 44.

The square root of 78129791 is about 8839.1057805640. The cubic root of 78129791 is about 427.5027251516.

The spelling of 78129791 in words is "seventy-eight million, one hundred twenty-nine thousand, seven hundred ninety-one".