78128131 has 2 divisors, whose sum is σ = 78128132. Its totient is φ = 78128130.

The previous prime is 78128081. The next prime is 78128161. The reversal of 78128131 is 13182187.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78128131 - 2⁷ = 78128003 is a prime.

It is a super-2 number, since 2×78128131² = 12208009707106322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78128093 and 78128102.

It is not a weakly prime, because it can be changed into another prime (78128161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39064065 + 39064066.

It is an arithmetic number, because the mean of its divisors is an integer number (39064066).

Almost surely, 2^78128131 is an apocalyptic number.

78128131 is a deficient number, since it is larger than the sum of its proper divisors (1).

78128131 is an equidigital number, since it uses as much as digits as its factorization.

78128131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 31.

The square root of 78128131 is about 8839.0118791639. The cubic root of 78128131 is about 427.4996974566.

The spelling of 78128131 in words is "seventy-eight million, one hundred twenty-eight thousand, one hundred thirty-one".