78305131 has 4 divisors (see below), whose sum is σ = 78774192. Its totient is φ = 77836072.

The previous prime is 78305113. The next prime is 78305147. The reversal of 78305131 is 13150387.

78305131 = 308² + 309² + ... + 641².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13150387 = 97 ⋅135571.

It is a cyclic number.

It is not a de Polignac number, because 78305131 - 2¹¹ = 78303083 is a prime.

It is a super-2 number, since 2×78305131² = 12263387081854322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78305131.

It is not an unprimeable number, because it can be changed into a prime (78305231) 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, 234280 + ... + 234613.

It is an arithmetic number, because the mean of its divisors is an integer number (19693548).

Almost surely, 2^78305131 is an apocalyptic number.

78305131 is a deficient number, since it is larger than the sum of its proper divisors (469061).

78305131 is a wasteful number, since it uses less digits than its factorization.

78305131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 469060.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 78305131 is about 8849.0186461551. The cubic root of 78305131 is about 427.8222888012.

The spelling of 78305131 in words is "seventy-eight million, three hundred five thousand, one hundred thirty-one".