78155849 has 4 divisors (see below), whose sum is σ = 78217680. Its totient is φ = 78094020.

The previous prime is 78155839. The next prime is 78155893. The reversal of 78155849 is 94855187.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 78155849 - 2¹² = 78151753 is a prime.

It is a super-2 number, since 2×78155849² = 12216673465821602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78155839) 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, 28979 + ... + 31560.

It is an arithmetic number, because the mean of its divisors is an integer number (19554420).

Almost surely, 2^78155849 is an apocalyptic number.

It is an amenable number.

78155849 is a deficient number, since it is larger than the sum of its proper divisors (61831).

78155849 is a wasteful number, since it uses less digits than its factorization.

78155849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61830.

The product of its digits is 403200, while the sum is 47.

The square root of 78155849 is about 8840.5796755643. The cubic root of 78155849 is about 427.5502470492.

The spelling of 78155849 in words is "seventy-eight million, one hundred fifty-five thousand, eight hundred forty-nine".