78643431 has 12 divisors (see below), whose sum is σ = 116238408. Its totient is φ = 51209424.

The previous prime is 78643393. The next prime is 78643507. The reversal of 78643431 is 13434687.

78643431 is a `hidden beast` number, since 7 + 8 + 643 + 4 + 3 + 1 = 666.

It is not a de Polignac number, because 78643431 - 2¹⁷ = 78512359 is a prime.

It is a super-2 number, since 2×78643431² = 12369578478903522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78643031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 101220 + ... + 101993.

It is an arithmetic number, because the mean of its divisors is an integer number (9686534).

Almost surely, 2^78643431 is an apocalyptic number.

78643431 is a deficient number, since it is larger than the sum of its proper divisors (37594977).

78643431 is a wasteful number, since it uses less digits than its factorization.

78643431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203262 (or 203259 counting only the distinct ones).

The product of its digits is 48384, while the sum is 36.

The square root of 78643431 is about 8868.1131589533. The cubic root of 78643431 is about 428.4375075373.

The spelling of 78643431 in words is "seventy-eight million, six hundred forty-three thousand, four hundred thirty-one".