78149261 has 4 divisors (see below), whose sum is σ = 82262400. Its totient is φ = 74036124.

The previous prime is 78149251. The next prime is 78149263. The reversal of 78149261 is 16294187.

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 78149261 - 2¹⁴ = 78132877 is a prime.

It is a super-2 number, since 2×78149261² = 12214613989692242, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78149263) 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, 2056541 + ... + 2056578.

It is an arithmetic number, because the mean of its divisors is an integer number (20565600).

Almost surely, 2^78149261 is an apocalyptic number.

It is an amenable number.

78149261 is a deficient number, since it is larger than the sum of its proper divisors (4113139).

78149261 is a wasteful number, since it uses less digits than its factorization.

78149261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4113138.

The product of its digits is 24192, while the sum is 38.

The square root of 78149261 is about 8840.2070677106. The cubic root of 78149261 is about 427.5382335309.

The spelling of 78149261 in words is "seventy-eight million, one hundred forty-nine thousand, two hundred sixty-one".