78240931 has 4 divisors (see below), whose sum is σ = 80764864. Its totient is φ = 75717000.

The previous prime is 78240913. The next prime is 78240973. The reversal of 78240931 is 13904287.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13904287 = 1223 ⋅11369.

It is a cyclic number.

It is not a de Polignac number, because 78240931 - 2¹⁷ = 78109859 is a prime.

It is a super-2 number, since 2×78240931² = 12243286567493522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78240991) 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, 1261920 + ... + 1261981.

It is an arithmetic number, because the mean of its divisors is an integer number (20191216).

Almost surely, 2^78240931 is an apocalyptic number.

78240931 is a deficient number, since it is larger than the sum of its proper divisors (2523933).

78240931 is a wasteful number, since it uses less digits than its factorization.

78240931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2523932.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 78240931 is about 8845.3903814360. The cubic root of 78240931 is about 427.7053373309.

The spelling of 78240931 in words is "seventy-eight million, two hundred forty thousand, nine hundred thirty-one".