28942639 has 4 divisors (see below), whose sum is σ = 31573800. Its totient is φ = 26311480.

The previous prime is 28942637. The next prime is 28942663. The reversal of 28942639 is 93624982.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28942639 - 2¹ = 28942637 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28942595 and 28942604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28942631) 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, 1315564 + ... + 1315585.

It is an arithmetic number, because the mean of its divisors is an integer number (7893450).

Almost surely, 2^28942639 is an apocalyptic number.

28942639 is a deficient number, since it is larger than the sum of its proper divisors (2631161).

28942639 is a wasteful number, since it uses less digits than its factorization.

28942639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2631160.

The product of its digits is 186624, while the sum is 43.

The square root of 28942639 is about 5379.8363358006. The cubic root of 28942639 is about 307.0289843084.

The spelling of 28942639 in words is "twenty-eight million, nine hundred forty-two thousand, six hundred thirty-nine".