78133191 has 4 divisors (see below), whose sum is σ = 104177592. Its totient is φ = 52088792.

The previous prime is 78133177. The next prime is 78133217. The reversal of 78133191 is 19133187.

Added to its reverse (19133187) it gives a triangular number (97266378 = T₁₃₉₄₇).

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78133191 - 2⁶ = 78133127 is a prime.

It is a super-2 number, since 2×78133191² = 12209591071684962, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78134191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13022196 + ... + 13022201.

It is an arithmetic number, because the mean of its divisors is an integer number (26044398).

Almost surely, 2^78133191 is an apocalyptic number.

78133191 is a deficient number, since it is larger than the sum of its proper divisors (26044401).

78133191 is a wasteful number, since it uses less digits than its factorization.

78133191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26044400.

The product of its digits is 4536, while the sum is 33.

The square root of 78133191 is about 8839.2981056190. The cubic root of 78133191 is about 427.5089263209.

Adding to 78133191 its reverse (19133187), we get a triangular number (97266378 = T₁₃₉₄₇).

The spelling of 78133191 in words is "seventy-eight million, one hundred thirty-three thousand, one hundred ninety-one".