78387291 has 16 divisors (see below), whose sum is σ = 116467200. Its totient is φ = 52106184.

The previous prime is 78387277. The next prime is 78387301. The reversal of 78387291 is 19278387.

It is not a de Polignac number, because 78387291 - 2¹³ = 78379099 is a prime.

It is a super-2 number, since 2×78387291² = 12289134780637362, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78387091) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5650 + ... + 13736.

It is an arithmetic number, because the mean of its divisors is an integer number (7279200).

Almost surely, 2^78387291 is an apocalyptic number.

78387291 is a deficient number, since it is larger than the sum of its proper divisors (38079909).

78387291 is a wasteful number, since it uses less digits than its factorization.

78387291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8455 (or 8449 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 78387291 is about 8853.6597517637. The cubic root of 78387291 is about 427.9718643251.

It can be divided in two parts, 7838 and 7291, that added together give a square (15129 = 123²).

The spelling of 78387291 in words is "seventy-eight million, three hundred eighty-seven thousand, two hundred ninety-one".