71428639 has 4 divisors (see below), whose sum is σ = 74534256. Its totient is φ = 68323024.

The previous prime is 71428631. The next prime is 71428691. The reversal of 71428639 is 93682417.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93682417 = 41 ⋅2284937.

It is a cyclic number.

It is not a de Polignac number, because 71428639 - 2³ = 71428631 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71428631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1552774 + ... + 1552819.

It is an arithmetic number, because the mean of its divisors is an integer number (18633564).

Almost surely, 2^71428639 is an apocalyptic number.

71428639 is a deficient number, since it is larger than the sum of its proper divisors (3105617).

71428639 is a wasteful number, since it uses less digits than its factorization.

71428639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3105616.

The product of its digits is 72576, while the sum is 40.

The square root of 71428639 is about 8451.5465448638. The cubic root of 71428639 is about 414.9133975191.

The spelling of 71428639 in words is "seventy-one million, four hundred twenty-eight thousand, six hundred thirty-nine".